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1954 CJ-3B "OB" Serial Numbers


"Open Body" Jeeps

Released for productionTodd Paisley's 2004 unearthing of Service Bulletin 328 dated 18 October 1956 and titled "Identification of Willys Vehicles" provides pretty strong evidence that the "OB" serial number prefix used briefly in 1954 indicated simply the standard "Open Body."

However, it doesn't state that fact explicitly, nor does it offer an explanation of why the prefix was used for only the first 2,600 Jeeps of 1954, before Willys returned to the 454GB2 series in use since 1950. (See some speculation about that in the discussion further down on this page. And see CJ-3B Serial Numbers and Production Figures for details on the old 1950-54 VIN series.)

Todd comments, "The breakdown of the prefix for the 1955 and 1956 model years finally answers the question. The OB stood for Open Body. There were 2 standard types (besides the special models like the Fire Jeeps) of Universal Jeeps: Open Body and Stripped Chassis. OB Jeeps were simply Jeeps with bodies."

For the 1954 model year, Service Bulletin 328 lists:

CJ-3B Universal Jeep
(First of Models Marked CJ-3B O.B. 54-10001 to 12,600)
454-GB2-12,001 (sic) and up.

For 1955, it deciphers the 5 digit prefix:

The first number indicates the year (5 for 1955).
The second and third number represents the series and body style.

Universal Jeeps - Series 7:

3. CJ-3B Open Body
4. CJ-3B Stripped Chassis
5. CJ-5 Open Body
6. CJ-5 Stripped Chassis

The fourth number represents the engine type:

2. 6 Cyl. 161 cu. in. F-head
4. 4 Cyl. 134 cu. in. F-head
6. 6 Cyl. 226 cu. in. L-head

The fifth number represents the drive:

7. All 2WD
8. All 4WD

57348-10001-21157 CJ-3B Universal Jeep - Open Body
57448-10001-11366 CJ-3B Universal Jeep - Stripped Chassis
57548-10001-23232 CJ-5 Universal Jeep - Open Body
57648-10001 and up CJ-5 Universal Jeep - Stripped Chassis

Released for production For 1956, they changed the definition again:

57 Represents the Universal Jeep line.

The third digit represents the body type:

Series 57

3. CJ-3B Open Body
4. CJ-3B Stripped Chassis
5. CJ-5 Open Body
6. CJ-5 Stripped Chassis
7. CJ-6 Open Body
8. CJ-6 Stripped Chassis
0. Special Jobs.

The fourth number represents the engine type:

2. 6 Cyl. 161 cu. in. F-head
4. 4 Cyl. 134 cu. in. F-head
6. 6 Cyl. 226 cu. in. L-head

The fifth number represents the drive:

7. All 2WD
8. All 4WD

A Special vehicle code is represented by a suffix added to theidentification number:

-01 CJ-3B Universal Jeep Fire Engine
-02 CJ-5 Universal Jeep Fire Engine

57048-01 * CJ-3B Universal Jeep Fire Engine
57048-02 * CJ-5 Universal Jeep Fire Engine
57348 21158 and up CJ-3B Universal Jeep Open Body
57448 * CJ-3B Universal Jeep Stripped Chassis
57548 23233 and up CJ-5 Universal Jeep Open Body
57648 * CJ-5 Universal Jeep Stripped Chassis
57748 10001 and up CJ-6 Universal Jeep Open Body
57848 10001 and up CJ-6 Universal Jeep Stripped Chassis

* Serial numbers consecutive with 1955 production

Surviving Examples

Figures published by the former Willys Club, which also appeared in summary form in Sessler's Illustrated Jeep Buyer's Guide show the same group of 1954 CJ-3Bs with the unusual VIN prefix:

1954 CJ-3B O.B. Jeep
O.B. 54 10001 to 12600 Total: 2,599

1954 CJ-3B Jeep
454 GB2 12601 to 41292 Total: 28,691

54OB 10027In fact, slightly less than 2,599 of the Jeeps seem to have ended up with the OB prefix stamped on their VIN plate, and some of them also include the 454GB2 prefix.

At right is early example 54OB10027, owned by Rick Rothermel in South Dakota.

Below is a list of 1954 Jeeps we know of with the "OB" numbers, from the list of Surviving CJ-3B Jeeps.

1954 Model Year

1954 54OB 10006 4J33528 Colombia Carlos Alberto Barrera Toro
1954 54OB 10022 Massachusetts, USA Dave Strickler
1954 54OB 10026 Florida, USA William Barrow
1954 54OB 10027 4J40447 South Dakota, USA Rick Rothermel
1954 54OB 10028 Illinois, USA Eric Kaiser
1954 OB54 10160 4J40627 Texas, USA James C. Kearney
1954 OB54 10193 4J40605 New Mexico, USA Grant Reel
1954 OB54 10227 4FR174105 Iowa, USA Jeff Thomas
1954 OB54 10386 4J41057 North Dakota, USA Ken D Gordon
1954 OB54 10479 Sweden Krister Yderholt
1954 OB54 10547 4737286 California, USA Eugene Troxell
1954 CJ3B54 10572 Arizona, USA Turk Sierras
1954 OB54 10595 4J41791 Oregon, USA J.R. Bass
1954 OB54 10830 South Dakota, USA Darrell Tracy
1954 OB54 10833 South Carolina, USA Lee Porter
1954 OB54 10871 Maine, USA Glenn Byron
1954 OB54 10994 Florida, USA Arden Brown
1954 OB54 11068 Arizona, U.S.A. Kevin Artz
1954 OB54 11221 Texas, USA Dale Jones
1954 CJ-3B OB54 11223 Texas, USA Markel Simmons
1954 CJ-3B OB54 11229 Ohio, USA Joseph A. Fay
1954 CJ-3B OB54 11301 4FR134584 Colorado, USA James Brewton
1954 CJ-3B OB54 11321 Connecticut, USA
1954 OB54 11353 Pennsylvania, USA David Weiland
1954 454GB2 12004 Pennsylvania, USA Harry Van Horn
1954 OB54 12022 4J42080 Colombia Yesid Gonzalez Torres
1954 CJ-3B OB54 12029 4J42080 Colorado, USA Ray Huffaker
1954 OB54 12031 Pennsylvania, USA Ben Sickler
1954 OB54 12037 Arkansas, USA Mark A. Gray
1954 OB54 12040 4J42387 Quebeec, Canada David Marcotte
1954 OB54 12141 Colorado, USA Jerad
1954 OB54 12148 Havana, Cuba Alejandro Alfonso Hernández
1954 54 12151 Indiana, USA Randy Farmer
1954 CJ3BOB54 12161 Mexico Ricardo González
1954 OB54 12195
1954 454GB2 OB12211 4J40693 Georgia, USA Jack G. Ahlberg
1954 OB54 12268 Texas, USA Paul Doskocil
1954 OB54 12272 Illinois, USA Paul Lengsfeld
1954 OB54 12281 Michigan, USA Michael Hurt
1954 OB54 12293 4J146872A Michigan, USA
1954 454GB2 OB12302 Connecticut, USA Michael Knap
1954 OB54 12314 4J42825 New York, USA Frank Porfidio
1954 454GB2 OB12328 Texas, USA Harry B. Gould
1954 OB54 12331 4J42736 Colorado, USA Stuart Lovelady
1954 OB54 12332 4J42841 Vermont, USA Alec Genung
1954 454GB2 OB12344 T58452 North Carolina, USA Ed Wilson
1954 CJ-3B OB54 12361


The VIN Plate

VIN tag

The majority of the serial number tags show a number starting with "OB54"(see Stuart Lovelady's OB54 12331 VIN plate, 80KJPEG). However, the earliest examples have a 54OB prefix.

The photo at right shows Carlos Barrera's CJ-3B 54OB 10006 from Colombia, now the earliest known surviving example. See also Dave Strickler's 54OB 10022, William Barrow's 54OB 10026, and Rick Rothermel's 54OB 10027. (The date stamped on the transmission of that Jeep is 10-20-53.)

Turk Sierras' slightly later CJ-3B 54-10572 (90K JPEG) omits the stamped OB entirely, possibly just a mistake. Some late examples are David Marcotte's CJ-3BOB54-12040 (150K JPEG), also CJ-3BOB54-12293 (120K JPEG) and CJ-3BOB54-12361 (60K JPEG).

The final group show an "OB" stamped after the 454GB2 prefix:   Ed Wilson says, "My stamped plate reads 454GB2 OB 12344, with the OB being stampedslightly larger and much heavier than the other numbers. It is obviously adifferent stamp than the rest of the line. The OB stamp may have been on a single die as they are even with each other, but high in relation to the rest of the serial."

Jack Ahlberg adds, "Mine is also neither a prefix or a suffix, but right in the middle of the serial number. It is of a different style of lettering and is stamped as opposed to being embossed. My number is 454GB2 OB12211. I do hope someone can give all of us an explanation one of these days."

What's Up With That?

As of early 2004, the exact significance of this variation in serial number prefixes has not been determined, although it now appears clear that "OB" stood for "Open Body." Discussion over the past few years has centered mainly on:

  1. Possible meanings for the acronym "OB" in the prefix, and
  2. Possible physical differences from later 1954 models with the 454GB2 prefix.


The only distinguishing physical feature that shows up with any consistency, is the original tailgate found on several of the surviving examples. (See also the tailgate on OB5412195, 70K JPEG.) It lacks two small cutouts in the upper lip, designed for the M38-style rear spare tire mount. Tailgates on all other CJ-3Bs appear to have those cutouts. For more details, see Tailgate Construction, Dating and Authentication.

With no other completely convincing results in either of these two areas, recent discussion on the CJ-3B Bulletin Board has moved toward focussing on:

  1. The fact that the "OB" designation was also used occasionally on other Jeep vehicles (although not apparently in the serial numbers) and may have been associated with Jeeps built on different assembly lines, or for special equipment orders.
  2. The possibility that "OB" was not an acronym and reflected no physical difference, but was simply an administrative change.
Because of the difficulty in summarizing the wide-ranging discussion, most of it is included verbatim below. We'll add further evidence to this page if it surfaces.

Overseas Built?
Discussion on the Classic Jeep Mailing List, 1997

From: Jerry Wagner Date: Mon, 22 Dec 1997

I don't have access to any production figures to back up this claim, but... The guy I buy parts from tells me that during the Korean War some military Jeep production was moved to Japan. According to him, Mitsubishi produced most of the Korean Jeeps as a subcontractor to Willys. At the end of the war the excess production was resequenced as "O.B.-XX-XXXXX" and shipped back to the US for distribution. If this is accurate, maybe the OB stands for "Overseas Built" or "Occupation Board" or maybe O.B. is an assembly plant designation like "Osaka Plant B." I plan on doing some internet research from this angle but maybe Todd or someone has a piece of info relating to the Japanese production?

From: Ed Wilson Date: Tue, 23 Dec 1997

I can't help but be curious about the Korean War/Mitsu built 3Bs. The shooting stopped there in July '53, pretty close to the introduction of the 3B here. The M38 A1 had been in service for roughly two years. How could the 3B have gotten to Korea for the war? Why, when the A1 was pretty well integrated into the supply system by that time? With the A1 on hand, seems our forces would have been looking to move the old M38s along, perhaps to an ally, a very common practice for older hardware. Perhaps the OB was built for the South Korean government, after the war, and for some reason was not delivered/accepted.

From: Morihisa Ochi Date: Tue, 06 Jan 1998

As to 2,500 CJ-3Bs exported to US in the end of Korean War, we have much doubts. Mitsubishi had the contract with Willys so they could not export to US. Do you have any evidences to prove this story such as photos, Data plates(O.B)...If you have, please send me.

Old Body? Offline Build? or Just Plain "OB?"
Discussion on the CJ-3B Bulletin Board, 2002-3

Chuck - 26 Aug, 12:56 AM

Well, it finally happened. I pick a "new" jeep as a commuter backup to the wifes dying Wrangler and it turns out to be one of those mysterious '54 "OB" models. Now, I still haven't figured out my special stiched vinyl, body colored (green) seats in my '56 and now have this other mystery to contend with. Just as a "seat of the pants" observation on this vehicle, one thing is plain, the springs are noticably stiffer than the '56 OR my '54 M38A1! Any insights or mumblings about the 3 BOB would be useful and appriciated. As for the '56 (seats), close as I have come was it was a special dealer promotional model to ring in the new year. Again, any insight into that would be highly appriciated. I hope to have a great time uncovering what I can about both and sharing what I can!

Stuart Lovelady - 26 Aug, 10:19 PM

I too have an example of the mysterious OB. The only thing that seems to connect them is discussed under tailgate authentication in the parts section of the specs and tech tips page. And that could be merely coincidence. Does your jeep have that mutation?

My 3 BOB (I like that) spent its early life pushing snow around, so it has only one modification that I'm aware of (oil filter moved to make room for hydraulic components).

The only other curiosity that looks original is a strange, somewhat semicircular spring attached to the left side of the rear axle. It's fairly close to the axle bumper (<1 inch), and the bumper shape itself looks like it was made to accomodate this thing. It's only on the left side, and I can't find either part in the catalog.

OB10027 Dash

Old Body

jyotin - 31 Aug, 02:59 PM

The conventional thinking on these is that the first x number of '54 jeeps had the OB54 prefix. After that they used the 454GB2 prefix. That's Ok, I guess, but jeep used the same prefix scheme on all their other models (wagons,trucks), it seems odd that they would change only the 3B for a short period of time and then change back to the expected prefix configuration.

I'd like to offer up a second possibility that it was the the last x number of jeeps manufactured in or about '54/'55 that were OB jeeps. Perhaps it was due to some sort of mixup and that the old style dashboard was manufactured for use in some '55 jeeps. Since the dashboard changed jeep needed to use the old units up rather than field modify them for new dashboards. Since the serial number scheme had already been changed to the new method across the jeep product line(s), they needed a special series of numbers to describe these 'orphan' 3B's. That would help to explain why only 3B's had the OB prefix scheme.

It would be interesting to know if some one who has an OB jeep could search the differentials, engine, and gauges (especially speedo) for any indication of manufacture date of the part. If it was late '54 or early '55, then maybe that would be a lead.....

The OB jeep that I found was too far gone to determine anything -- It even had a flathead engine! All I rescued was the serial number plate.

Ed Wilson - 31 Aug, 05:16 PM

jyotin's theory is very interesting and makes sense. "OB" may be no more complicated than "old body". But it would sure be great if, at some time, some "hard" evidence should surface regarding these 3Bs. I will check the speedo on mine. My normal 3B has a date stencil of Aug 54 on the speedo. A later date on the OB might confirm jyotins's thinking. Considering the fall introduction of new models back then, Aug is rather late in the production year. But who really knows what Willys was up to with retitling of unsold Jeeps for the next model year.

Don't we love a mystery!

Derek Redmond - 05 Sep, 09:47 AM

I'm glad to see somebody thinking "outside of the box" on this question again. But the numbers do pretty clearly show that the OB's came at the beginning, not the end of the 1954 model year. See https://cj3b.info/SerialNos/SerialNosEngine.ht ml for the chronological list of VIN's in the CJ-3B database.

And the new dash didn't actually appear until 57348-34452, early in the 1957 model year.

I like the "Old Body" theory though. Like Jim, I have always thought the most logical meaning for OB was "Open Body", but it's not very satisfying, since all 3B's were open body. Supporters of the tenuous "Made in Japan" theory have suggested that it means "Overseas Built" or "Occupation Board."

I agree that close examination of the surviving examples will probably eventually produce some more clues.

jyotin - 26 Sep, 06:52 PM

OK guys, let's take all this one step further. How 'bout we simply add together all we discussed on the previous thread on this subject.

Here is a scenario ----

In or about 1954 and considering jeep planning for '55 and '56.

Jeep was about to change to the speedo cluster for the new line of CJ5 / cj6. It was to be the king - seeley with willys logo.

The DJ3A was being developed to be introduced with the large speedo.

All the rest of the jeep product line used large speedos.

The only application still using the separate gauges was the '3b.

Jeep had to use up their old bodies / dashboards or rework the old bodies -- they chose instead to use them up.

So, jeep decided to use the OB code to indicate old body BECAUSE they were due to switch to the new speedo in the '54 model year sometime.

Well, (and if any of you have ever worked in manufacturing planning for a large corporation you will agree that this is not much of a stretch) the buyers screwed up and committed for too many old bodies in the manufacturing pipeline (from their body vendor). Therefore, early in the '54 model year it became obvious that it no longer made any sense to differentiate old body (ob) from new body because it was going to be several years before they actually used up the supply. Therefore they dropped the OB from the '54 serial numbers. This is what they did to the body parts carrying the willys logo after Kaiser bought it.

Another manufacturing reason for this could be that jeep had a gazillion extra speedos (the old style -small) and gauges from the manufacture of M38A1 jeeps. The contract was cut back or a follow on option order was cancelled and jeep either had to eat the gauges or use them up. So they delayed introducing the large speedo 'till they used up their old stock. -- Same logic for discontinuing the OB designation.

In addition, there was a recession in '56 and the automobile industry was hit hard. Demand for 3b's dropped so that the rate at which they used up old bodies slowed.

Time passed and they still were using up old bodies.

By the time they were ready for the New Body, they had changed their serial number naming scheme to 57548, and no one really cared at that time whether the serial number indicated an old body vs a new body.

Perhaps it was related to a change of ownership -- Kaiser??

I have always thought that the OB jeeps were coded OB for some administrative reason and that OB really had little meaning outside of that.

Derek Redmond - 26 Sep, 09:49 PM

Very interesting -- thanks Jyotin. Your theory makes a lot of sense, and gives us some good things to think about.

I haven't really had a chance to think it through, but there are a few things that bother me about the theory:

1) I don't think Willys was prone to creating new series of serial numbers to mark changes in details of manufacture of an existing model.

2) The change from OB numbers back to 454GB2 numbers is not clean -- there is a bit of overlap.

3) I don't think the military gauges on the M38A1 were the same as the small gauges on the CJ's.

4) Kaiser was already in charge by this point, and why would they be overly concerned about a change in the dashboard, since they would continue to use the WILLYS-stamped body parts until the eary 60's?

I'm curious whether you have any other reason to think that the OB numbers were an administrative detail rather than representing some concrete difference. Aside of course from the obvious fact that we haven't been able to find any real difference...

Chuck - 01 Oct, 05:22 PM

I'm still crawling over the 3BOB but haven't noticed anything that the '56 does or doesn't have. However, my M38A1 bears testimony to the fact that Derek is right, the guages are nowhere near the same. The dash construction is the same in both 3B's although the different gages. A '53 Harrison radiator resides underhood and I will be digging underneath and more indepth Oct.2-3rd.

jyotin - 04 Oct, 01:41 PM

Derek A couple of answers to your questions---

First, on the gauges -- you are right they were different. My bad. The facts still support the scenario.

The OB serial number cutoff looks fairly clean. Some jeeps had OB in the center or the end of the serial number, but they had OB indicated just the same.

I haven't the foggiest reason as to why jeep might want to indicate a sub variant of the 3b(old body). Perhaps they were concerned that they might have to reference it in their parts manuals. I'd love to see the '53 cj3b manual as well as the supplements 1,2,and 3. In the book issued in '56 there is no reference to the OB series.

At any case, it appears to me that they abandoned the OB designation in favor of the standard serial number. Because there has never been any reference found anywhere relating to OB, and because the parts manuals don't differentiate, and because no one has been able to nail down a difference between OB and 'normal' 3b's, I think that it was administrative as opposed to a difference in specification for the '54 model.

The production numbers for '3b's dropped in '55 - '57 (when dashboard changed). If Jeep production planning (for '55, '56) had straight lined the sales volumes based on '53 and '54, they would have put around 31000 units in the pipeline. Sales volume did not materialize, and about 31000 units later they switched dasboards. It took a couple of years to burn off the inventory that they planned to sell in one year.

So, initially they could have wanted to separate the old body from the new via serial numbers --Why? who knows? Again, when it became apparent that it would be several years before they would use up the inventory they dropped OB. By the time the change rolled around, no one thought it a particlarly good idea to identify the body differerence using the old OB scheme.

Other instances of jeep using up old inventory

CJ5 cowl (24 volt battery cover) CJ5 hood (snorkel opening) Willys logo (anywhere) Speedo clusters (with WILLYS logo)

Why they did not indicate any of the above instances in the serial number is that the dashboard difference was the only 'old part to use up' that could make a difference in part replacement.

As a side note, I found that they switched from the original tail lights to the Hall tail lights with the same serial number as they switched to the large speedo cluster.

I'm going to be talking with someone who worked at jeep for a long time next week and I'll see if he has ever heard about OB.

If it was a production ordering error, there was probably no one who wanted to claim it and jeep sure wouldn't document it anywhere.

I guess we have too much free time.....

Chuck - 07 Oct, 06:06 PM

jyotin; your theory is starting to make some real points here. After crawling all over this thing for some time (I'm still not finished), it seems that nothing (yet) is different at all. I have yet to find anything that is NOT on my '56 other than the gages and the fact that the "OB" has what appears to be a military type horn. I cannot yet certainly identify this horn as the '56 has a "special" horn from '56 that is not the same as other horns found in jeeps of the era. It makes it a little more difficult in that the '56 is not run of the mill either. Also, the wife is busy driving it to the bus stop and many out of town trips have precluded me from digging deeper. Sometime after Columbus day, I HOPE to post anything that I may find.

Derek Redmond - 13 Oct, 09:40 PM

Jyotin, You've got a good argument, particularly given the lack of any evidence of significant physical difference.

Yes, you are right that the change back to normal serial numbers was clean. In fact, our list of surviving Jeeps at https://cj3b.info/SerialNos/SerialNosEngine.html shows a substantial and unexplained gap in consecutive numbers where the normal numbers resume. The gradual change in where the OB appeared in the serial number is puzzling, but not really inconsistent with your theory.

I'm still dubious about why Willys would have done this, when it wasn't their standard procedure. And I don't really buy the suggestion about their projection of continuing huge sales; I'm sure they knew that when the CJ-5 came online, the 3B would immediately become second banana.

However, I am also puzzled by the exact significance of the terms "Final Old" and "Face Lift" which appear for serial numbers 63370 and 64401 in the list of CJ-3B serial numbers by month for 1960-62. This sheet can be found down near the middle of the page at https://cj3b.info/SerialNos/SerialNosSixties.ht ml

These notations are perhaps another indication of administrative recording of serial numbers where minor changes were made.

Chuck - 14 Oct, 12:51 PM

Well, on examination of the whole jeep, I have found only three differences between the 3BOB and my '56. The first is the fact that the "OB" prefix is at the start of the serial number rather than in the middle or at the end (no difference actually as the '56 is obviously not an "OB"). Second is the horn as stated before but I only have the M38A1s horn to compare it to since the '56 has a special horn unlike any other jeep I have come across. The third is the way the wiring harness goes along the side to the back as in the '56 it is along the left side upper lip while it is along the bottom on the 3BOB. Any other differences have not been noted other than the fact that the '54 is as any other '54 and not as a '56. This jeep is not mine but my wife's and she doesn't share the enthusiasm of the mystery as I do. Besides which, the "OB" is not as willing to share its past as much as my "promotional" '56 with the 2nd "original" owner still relating pieces of information. Any further insights or guesses would be more than welcome. Thanks for the "info" as it now stands and happy jeepin'!!!

Off Board

Chuck - 31 Jan, 12:51 AM

Chuck's heater hoses I never got a chance to get back online with further info concerning the '54 3B "OB" when we were discussing it back a couple months ago. However, after learning about the "W" clip used to hold the heater hoses and that some folks concidered that O B meant Open Body, I went through some research concerning this and found that this just couldn't be true. An open body jeep would not have been equiped with a heater option as this one was. The heater obtained with the jeep was the original Willys Harrison although somewhat chewed up. The engine had the "W" clip and also had new brass plugs where the engine connections would be. In addition, every original item on the body indicates that an original top was once in use as per Bart's exhaustive research. Then comes the "complete, exhaustive, Willys Production Figures which list "every vehicle produced by the Willys company" which lists every prefix under the sun EXCEPT the OB prefix. There is also something refered to as 'off board'(?) that I have only seen one referance to. One explanation given to me is that it may have been an engine originally designated for another use but then used in the "OB" jeeps to fill some kind of gap or lack of production but then why no records? If anything, the more I dig, the more the mystery deepens.

Rick Cool - 31 Jan, 09:28 PM

Chuck, I suggest that you are on the right track, but that "OB" may stand for "Other Body", meaning Willys provided the parts to someone else to assemble because of a shortfall in production line capacity at their facility. Rick.

Chuck - 01 Feb, 11:16 PM

Rick; that sounds about right. I don't know what the reference to "off board" meant beyond the fact that maybe it meant that it was off the assembly line. It still begs the question though that if there was a shortfall, then A.)why no production figues and B.)why such a small production run. With such a small batch, it would seem that Willys would have no trouble incorporating those few vehicles into their regular assembly process. However, if it were not a 'normal' process, then maybe the off board reference was used to indicate that these vehicles were built using excess parts lying around. Sort of a factory second as it were. There is still no reason why Willys would leave the production figures out of the bottom line. By the way, one non-jeep neighbor suggested that maybe the jeep was a special (such as Laredo) and that off board meant that the production was keapt off the production board!?!

Administrative Changes

jyotin - 02 Feb, 03:59 PM

I have seen OB refer to open body on some of the DJ3A production figures. They were at the bottom of some original data that I think I got from the 3B page.

The only open body jeep in 1954 was the CJ3b -- the 3A was out of production and the CJ5 was not yet in production. Perhaps jeep was going to differentiate for some reason initially, but gave up the idea some 2500 or so jeeps into the production year?? They re- incorporated the open body designation in '64 or so. In '54 it may have been associated with the fact that they were changing the entire serial number construct for the '55 model year.

Open body designations were part of the serial number construct later when the "05" as the third and fourth digits meant open body on CJ's. It appears that this 'open body (05)designation included jeeps with heaters and without -- with softtops and without, and with hardtops or without.

I think that we have pretty much determined that an OB jeep was the same as a "normal" '54 jeep, so I still think that it was some administrative reason that OB was added to the serial. I believe that it was abandoned after some production for another administrative reason that we will never know.

I talked with Don Snowden (long time jeep corporate salesman), and he had never heard anything about "OB" jeeps.

Glenn Houston - 03 Feb, 06:19 AM

I don't have a 3BOB and don't think I ever saw one, but after reading all the coments over the last several months there is something I was wondering about. Kasier bought out Willys Overland in 1953. Changed the name to Willys Motors. Is there any records of when in 1953? Since Willys built some 1953 models in the last part of 1952 where they also building 1954 models in last part of 1953? What does the plates on the dash of the 3BOB's say , willys Overland or Willys Motors? where the 3BOB's built before the first of 1954 and then the s# changed starting with the first of 1954? Just wondering.

Chuck - 04 Feb, 11:22 AM

Glenn; My plate is Willys CJ-3BOB ##### with Willys Motors listed on the bottom. I will be sending in photos to Derek as soon as the film is developed. I can't answer your questions concerning dates however. I will dig around it today if it gets warmer and try to get the dates off the heater, radiator, distributor, starter, etc. and make a list of the numbers, types, dates, etc. I remember what you were stating the last time this came around, about the change in ownership and the change in serial number progression but still wouldn't explain the lack of production records or at least referance to what was being attempted. I think all the suppositions are right to a certain point but to what degree? My wife (the owner of 3BOB) has her own therory that it might be an ex-fire jeep although she bases this in part on the original red paint. The milage of 3BOB is a little over 15000.

Chuck - 04 Feb, 12:57 PM

I shouldv'e waited to post. Jyotin made an observation that had me thinking about when Kaiser took over Willys and what their incentive would have been to change the serial numeration. Since Willys was based in Ohio, there was no need to differentiate but when Kaiser took over, maybe there was an initial preceived notion that there be some type of factory notation, like OB = Ohio built? The recognized facts that the 3BOB was built in early '54/late '53 seems to be acurate by any figuring, the radiator is listed as 53K. The firewall data plate is listed specifically as; CJ-3BOB 54-12195 The second "B" is a double stamping. Why the listing on the plate as to it being a CJ-3B or an OB '54? And the other, why did the numeration begin at 12XXX? Did the "regular" 3B have a corresponding 12XXX or is there a serial # gap? Were these the very first Kaiser 3B's and were to undergo some type of 'CJ4' transfiguration that somehow never materialized? Too cold right now to check on those tags...

Derek Redmond - 06 Feb, 03:09 PM

As far as I can tell, 1954 CJ-3Bs with the OB54 prefix started at serial number 10000 and went to approximately 12500, where the regular 454GB2's begin. However, some or maybe all of the last couple hundred OB's actually have the prefix 454GB2 OB.

See https://cj3b.info/SerialNos/SerialNosEngine.html for the listing of OB's I know of.

Brian Hurt - 04 Mar, 06:17 AM

I have just recently acquired a cj3bob. I had no clue about the mystery on the prefix until someone told me to check over here. I work at a ford plant and i'm trying to rack my brain to figure out what they might have done. I looked a little at the owners board and some of the info on the serial #'s but I'm not sure when the ob's were ran. Were they built the first part of the model year? If they were it might have something to do with mixed parts from both model years. to me the b might stand for build, but what the o stands for I can't think of anything right now. Might they have been pre production run's? now they test run the new model down the line so they can build a couple of the new model year and drive and test them out. Now they just crush them after they are done, but maybe they sold them afterwards?

10027 taillights not original

Parts Differences

Glenn Smith - 11 Mar, 09:16 PM

I've been thinking on my own theory of the OB saga. I believe that others have said that a 3B body tub is only different than a 3A tub in the firewall of course, and the filler piece added in to raise the cowl. I guess the basic facts are '53 was the last year for the 3A, and if I understand correctly the first 2500 3Bs' for '54 were the infamous OBs'. What if these were really originally 3A tubs not needed and were modified to be 3B tubs. Maybe even the 3A frames were used too? Again if there are differences in the 3A and 3B tubs other than the above mentioned please enlighten me, because I don't have access to a 3A to compare with. Same with a 3A frame, is there a difference in the 2 frames? My '59 3B has a repro tub so I can't check it against anything for accuracies.

Derek Redmond - 14 Mar, 07:23 PM

Glenn, your idea is an interesting variation on Jyotin's "Old Body" theory, in which there is no real physical difference between the OB's and any other 1954 CJ-3Bs -- just an administrative record of which old parts were being used up.

Brian Hurt - 20 Mar, 07:17 AM

All right, I checked the tailgate a few minutes ago and it has the square notches and the rounded notches along the top. SO its not one of the mystery tailgates. I'm hoping to take the body off in a week or probably 2. The snow's gone, but now I have the mud. it needs to dry out a little before I can do much outside. As soon as I find out all the numbers I'll post them along with any pictures I might take. Glenn, I'm with you on that theory about using old parts. It makes sense to me at least.

Just a note on the tailgates regarding the punchouts being painted at the factory and no footman loops... I'm guilty of it at work too. soo many options, sometimes you just do it anyways to that car. 50 years from now someone is going to try restoring a continental and wonder why there is a J-clip on the body without anything attached to it. Its gonna cause one of these type of discussions;)

Glenn Smith - 20 Mar, 09:22 AM

Well, I won't take credit for the "old body" theory, but I didn't recall reading that anyone had thoughts specifically on the 3A leftovers (if there were any). Thus I approached it from that angle, since the time frame fit seemed to fit perfectly. I was hoping some more people would offer more thoughts on the subject.

Keith Buckley - 03 Apr, 02:10 PM

I have a challenge for you 3BOB folks.

Do you have a toolbox under the passenger seat?

The CJ2A OB's had a special body part number that deleted the underseat toolbox to ease installation of welders, generators, and farm hydraulics.

Althought the OB may have started as open body, at least for the CJ2A it just meant that the vehicle was destined to be shipped out in non standard form to have other equipment added. I've found records of contracts for the Coast Guard and South African Gov't that way.

I hope to have the same info for 3B's in the next month or two...

Chuck - 03 Apr, 09:44 PM

Hey Keith; Mine has the toolbox. Thanks for the input, every bit helps and it may be that what you state is true. Maybe Overseas Batch? :>)

Derek Redmond - 05 Apr, 02:54 PM

I haven't heard about CJ-2A OB's before, Keith. Does the designation actually show on the serial number? Any idea how many, and whether they usually come in batches or just randomly? Remember, with the 3B's we're talking about something like 2500 consecutive Jeeps.

Photos I just got from Keith Hepper clearly show a toolbox on his OB.

Order Build

Keith Buckley - 08 Apr, 04:30 PM

Bill of Materials I've been studying some recently acquired documents (copies). It appears that sometime between 1947 and 1948 that the "Bill of Materials" format changed. Since more Jeep models were being manufactured, and shared parts, the bill of materials was more generic, and each section had its own index. In this newly introduced index was a box for "OB". Text below it stated that all vehicles shipped out for completion of assembly elsewhere were to be shipped "OB". (I wonder if this is Outbound???) One of these examples was the Farnsworth GE welder Jeeps. It even provided the address of the facility the Jeeps were shipped to to complete the assembly. Actually each modified version of the body had a different part number, and the part number changed each time the paint color was changed. (I was always told they were completed at Stickney Ave. This is not correct.) The Jeeps were shipped to a vendor on Ketchum Avenue, a few blocks from Stickney. Before you drive down to try to beat me to whatever might be left of the old facility, I've been there. It is now an exit ramp on I 280...

If you look at the 1967 model index I sent you ages ago on form 947040, you will find that there are columns for OB1, OB2, OB3, OB4, as being distinctly different sub models within each model type. This really screws up my original thought that the pictures in the Service manual of "Open Body" meant stripped or no top.

Chuck - 08 Apr, 05:05 PM

Keith; Well, that would make sense why these 3B "OB's" have different prefix for different batches. Some start with ###OB##### or OB##### or whatever. SOrt of like the OB1, OB2 maybe?

Keith B - 09 Apr, 09:15 AM

The more I dig, the more it is obvious that whatever "OB" stands for, it is definitely always a specila order or special purpose build. I've mailed you 2 jpegs, one of the B/M Master Index Page 226-69, dtaed 6-11-48, Titled Special Vehicle, Minimum Agriculture. It lists the part number for a complete CJ-2A 'standard' as 656170, and then lists the individual B/M for each group of components such as draw bar and bumper weights. I have reviewed several hundred pages, and all the 'special' vehicles such as welders, firetrucks, etc all have "OB" Body type designations, even if they have a top.

I also sent you the 'generic' Bill of materials showing how the type of form used when parts were applied across more than one vehicle type. The two main classifications are MODEL and BODY TYPE. This is dated 7-14-48 and shows clearly that the CJ2A and CJ3A were available as OB Body Type. (Body types are listed as All, OB, SW, UW, SD, VJ-2, SS, CAB, PU, ST FFC, CL WS, ST CH.)You'll notice most are recognized abbreviations except SS and OB. Could OB be 'Order Build'? SW=Station Wagon UW=Utility Wagon SD=Sedan Delivery VJ-2= Jeepster SS=? Cab=Cab& Chassis PU=Pick Up ST=Stripped Chassis FFC=Flat Faced Cab CL WS=? ST CH= Station Chassis

Chuck - 09 Apr, 01:09 PM

Keith; Seems to me that someone else also came up with the "order build" theory. I wonder if anyone has thoughts on the SS designation?

Glenn Smith - 09 Apr, 02:23 PM

How about "Special Service"? Anyone else suggested that? I thought I saw before in the serial numbers list that the OB models were the first 2500 built. If so does that mean they designated them to be set aside to be completed as orders for special models came in? I have no knowledge on any of this whatsoever, but think it is an interesting and intriguing discussion.

Chuck - 09 Apr, 10:29 PM

Well Glenn, I'm no more "in the know" then you except my wife has one of these beasts. But it IS odd that if the "OB" was for special orders and such, why was it for such a specific amount and why only for 1954? I mean, how would they KNOW they needed 2500 units? Why none for suceeding years? Seems everytime answers are given, more crop up. And if I remember from this very page, didn't firejeeps have their own prefix? I am heading there now.

Chuck - 10 Apr, 12:19 AM

Interesting. '55's had the 57048 prefix for 3B & 5's designated as fire trucks. '54's had no seperate prefix on the list for fire jeeps, or any referance to them. However, there was a fire jeep in the lineup that included a '54 "OB".

Glenn Smith - 10 Apr, 09:12 AM

I'm not in the least trying to dispute Keiths' theory, but the fact that no one has seen any noticeable difference between an OB 3B and the others seems to do just that with the 3Bs. On the other hand we could wonder if the 2500 OBs were originally for an order that fell through? Maybe they ended up being just like regular 3Bs, but kept the OB prefix? Also, Rick Cool suggested "other body", assembled somewhere other than the normal factory. How about "other builder", thinking along the same lines. Maybe labor shortage, strikes, etc?

brian hurt - 12 Apr, 06:52 AM

Wow, alot to think about since I last checked in. I started to remove the rusted out body on mine and I noticed on the taillights it may be a 64 body. I remember a friend telling me once he could tell an older car just by looking at the part# on the tail light. They changed every year or something so they had the year in the part#. Haven't gotten to the frame serial # yet. Hopefully later today I'll get the cowl/firewall off so I can check that out. I did have a toolbox on mine, but I don't think mine counts in this case...

Just a thought here, Are we sure these ob's were made in order? when we build "odd lots"- exports, herse models, limo models... they have a different vin# but we don't make them all in a row. Usually as they are needed. But they eventually use all the vin # in a row. for example- all expeditions start out with 1FRM. 1FRM(U17)### is a mexican export, 1FRM(U15)### is a canadian export...

jyotin - 14 Apr, 05:24 PM

A comment on the possibility that OB could refer to 3A bodies that were 'converted' to 3b bodies.

The 3A dashboard is formed the same as a 2A dashboard, and therefore has the recess built in for a column shift even though it had not been used for years.

So, in order to change from a 3A to 3B they would have to scrap out the dashboard as well as add the spacer. That means removing spot welds and welding in a different dash. It would make more sense to put in the spacer and not replace the dash if they were going to do this.

I think that this conversion from 3A to 3B is very unlikely. And even on the outside chance that it was done, why in the world would they want to track a production / ordering error into the future if it didn't make any difference in the end product?

It is an interesting mystery, but I still stand on the side of OB being some sort of administrative attempt to change the serial number and a subsequent scrapping of the idea 2500 jeeps into the season, perhaps in preparation for the new serial number scheme that would go into place in '55.

I can think of no reason why jeep would want to track a canceled order forever in the form of a serial number. If they did, they would have started 1954 'normal' jeeps with 10001 and not 12500.

The '54 parts lists refers to early '54 serial numbers as 54-xxxx when differentiating parts that changed with a given serial number. There is no reference to "OB' anywhere in the parts manual.

The saga continues....

Chuck - 14 Apr, 11:38 PM

It takes alot for me to peck out these messages and my last one would not get on board no matter what I tried. Had I suceeded, jyotin might have saved himself the same pecking. As Keith stated (in not so many words) for the 2A & 3A jeeps, these were "order bodies". Since there seems to be no prefix designation for onboard welders, farm equiped vehicles, fire jeeps, and the like, an "OB" prefix would take care of the whole lot. After '54 they went to a more individualized type prefixing. There really is no difference between the earlier and later 3B's and the "OB's" with the exception of that tailgate. I thought my wife was a little nutty to suggest that maybe her 3BOB was initially a fire jeep but why not? The bed has been swapped out, otherwise, literally EVERYTHING is painted red (engine, oil pan, starter, trans, etc.). OB built jeeps would then be coming off the line alternatly with 'regular' 3B's on an 'as need' basis. Made to order if you will. That would also tend to bear out the reason why the OB prefix was in different locations in the vin scheme since there wouldn't have been any large scale steady stream coming off the line but rather small batches or individual vehicles. By '55, Kaiser had got hold of the numbers game, dash instrumentation changed, vehicles built for specific uses pretty much had specific prefix's. As later OB vehicles mutely testify, the prefix became a number with the OB in the vin so the total OB build out would probably be something over 2500, not an even, rounded number. So, where does that leave it? Seems to me that by discussing the subject and batting it around enough, it sort of answered itself (along with that documentation) that these were simply a platform vehicle for other uses rather then a straight off the line 3B.

jyotin - 16 Apr, 04:43 PM

I'm confused by the previous posting.

If I understand what was said --

Jeep reserved 2500 serial numbers in advance for special build jeeps.

Jeep would have then begun normal production with 454GB2 12501

They co-manufactured the two models on the same line.

So, as the assembly line pumped along, out pops 454GB2 20001, and the next jeep off the line could be OB54 10001.

And there is no difference between the two jeeps?

Given the above production run,what would prompt jeep to manufacture OB54 10002 instead of 454GB2 20002 as the next jeep off the line ?

Glenn Smith - 16 Apr, 08:51 PM

I agree that with the effort involved to modify a 3A, firewall, spacer and dash, that my theory was a longshot. I was thinking along the lines of them wanting to be able to show what happened to old inventory however, thus the OB. The fact that some previous Jeeps were also built as OBs blows that away. As I see it though, the fact remains the first 2500 '54s were OBs, and apparently no one has found any differences in an OB and a regular 3B.

CJ-3B and M38A1

Offline Build

jyotin - 16 Apr, 09:12 PM

There have been a couple of good ideas come out of this. This is a long shot -- speculation of course, and biased by my posit that this is an administrative item only, and not a difference in jeeps.

How 'bout a different way of manufacture? Suppose for a minute that Jeep was going to attempt a different method of manufacture for a group of jeeps that was a pilot (experimental) method.

They would identify a block (2500) of jeeps that would be manufactured using new techniques to compare with the standard line and do cost analyses to see if the proposed method of manufacture resulted in lower cost.

The differently manufactured jeeps would be done on a different line and could even be done simultaneously with the 'normal' jeeps. Heck, they wouldn't have to even be made in the same location!!

Now, this is only one of my several guesses, but any of my guesses all center around administration, and not unique models....

However, using manufacture date info on various components (speedo, axles, etc) could easily indicate whether or not there was any simultaneous manufacturing going on at Jeep at that time.

Frankly, I don't think we will ever know for sure unless some person in Jeep management from that time surfaces and tells us....

Keith Buckley - 17 Apr, 11:24 AM

You may not be far off with the idea that it was a change in manufactuing location. They commonly moved assembly lines from building to building. Before you scoff at that idea, an example would be when they moved the 3B paint line to accomodate the future production of the M151 Army Jeep. I'll check the dates. I thought that didn't happen till 1957. But it is an example where they would have built up painted bodies in advance.

I was looking at some data plates yesterday and on some of them I can't even tell the difference between the GB prefix and the OB prefix.

What does "GB" stand for anyway?

"OB" = Offline Build?

Bill Norris - 17 Apr, 01:58 PM

Using that theory could it be possible that these Jeeps were assembled in California? According to the 1948 year end report, Willys was experimenting with assembling Jeeps on the west coast to make distribution easier. I want to say it was in Maynard California??? I believe that they made 3,028 in California that year. I will have to dig out the report and check. Could that would explain the consecutive serial numbers?

Keith Buckley - 17 Apr, 02:00 PM

I think we're getting closer.

This is a CJ2A reference.

Running Change 2979, S.6 5-5-48

specifies part number 669461 as:

"BODY ASSY. PURCH. (less toolbox assy.)" included under several references

"After first 28088 Cars, After 1945 inventory CN 2024, S.5, up to first 44690 OB line cars."

It seems the "OB" line was a separate manufacturing line

Keith Buckley - 17 Apr, 03:17 PM

It was Mayfield California, and that may explain the CJ2A, but I don't know if they closed the plant by 3B production. I also know the other OB products were made in Toledo and shipped down the street to middlekauf to finish.

Mayfield was a CKD facility

Bill Norris - 17 Apr, 04:35 PM

Just checked the reoprts. You are right it is Mayfield. I show reference to the plant in the year end 1951 report. In 51 production rose to 5,000 units assembled there. I will get a copy of the 1952 report in the next week or so. I will look in the Kaiser file to see if I can find anything there for 1954.

Glenn Smith - 17 Apr, 08:43 PM

A couple of things here. First didn't Ford make the M151s? Also, where did Willys make the M38A1s? Maybe Willys was heavily involved in building them at the start of the '54 model year, necessitating the need to build 3Bs elsewhere?

Chuck - 17 Apr, 10:05 PM

The M151 is a MUTT built by Ford. I thought Keith was on the right track with the OB being a platform vehicle for special use and then POW!!! all of a sudden this thread is discussing the fact that (maybe) all the OB vehicles are built in Cal. Is this now the concensus that Willys built ALL OB vehicles (CJ2A, CJ3A, & CJ3B's) in Cal. up until '54 when they suddenly stopped? But then the reference to "other OB products were made in Toledo"? Glenn, by far and away 1952 & 53 saw the largest output of M38A1s. I have a 54 and the numbers really shrank that year due to the ending of the Korean conflict the prior year. '55's production were up from '54. To those who have these "lists", I would like to know where the farm jeeps, welder jeeps, tow jeeps, fire jeeps, airport jeeps, et al, fit into the OB prefix. There did not seem to be a seperate prefix designating these vehicles prior to 1954.

Brian Hurt - 18 Apr, 05:16 AM

Keith, The "ob line cars" may just mean line of cars. as in a style of cars, not actually an assembly line?? Just a thought. I keep putting off looking at my ob, but I have the next 4 days off. Later today I want to tear into the jeep and I'll let you know what I find out about the serial #'s on the frame. I'm 99% sure that body is a donor. As far as setting aside a certain # of serial #'s, I'm still going with pre production runs. Thats just the only thing that makes sense to me. Working for ford, if it sells, build more. It would be quite a coincidence that exactly 2500 were made and they knew in advance to build them through the year and be able to predict that number when they assigned the rest of the 3b serial numbers. After reading everything else again and again, thats my theory...

"GB" versus "OB"

jyotin - 18 Apr, 08:40 AM

Lets keep in mind as we go down yet another avenue, that in 1954 (actually after august 1953) that there were no modern production techniques using PC's, barcodes, just in time inventories, etc.

You couldn't do nearly the custom production work on the line that you can do today.

Production lines were much more manual and not as easily changed as they are today.

I think someone above asked an interesting question, so I will repeat it and elaborate a little.

454GB2 1954 cj3b 453GB1 1953 cj3a OB54 1954 cj3b

What was the G for? What was the B for? We have been concentrating on the "O", but knowing what the G and B stood for could clear things up.

We will probably have to go back to documentation from '50 or '51 to find out since that is when the GB first appeared in the CJ3A.

Here is a link to some serial numbers (this is probably on CJ3B.info too) http://www.off-road.com/jeep/tech/history/serial.html

Check out the 3B,3A,station wagon, trucks, and cars in the 51-55 time period. Note the use of the "B" in the prefix -- it was used on trucks,wagons,cj's and even cars.

No where is the G used except on cj's. It could be reasonable to assume that the "B", whatever it meant did not mean BODY, but was some single digit code for something else.

It would also be reasonable to assume that "G" alone was the code for the CJ line of vehicles until early in the '54 model year. So what's the "O" for? So why was it swapped back?

This is the circle that always brings me back to the idea that there was no physical reason to use OB, and that it was either some sort of colossal mistake, or some administrative attempt to track something that was abandoned later in the production year.

No where in the series of serial numbers did the "O" appear.

As a side note, the stripped chassis cj's were "GA" vehicles.

jyotin - 18 Apr, 09:40 AM

I left out one thing that I meant to put in the last post.

I think that when we think about this that each digit - O,B,G,F,A et al need to be considered as separate items, and not together. The serial numbers show that.

You may also note that the letter prefixes (the first letter in the prefix) in the wagons are in an alphabetic range, and that there is a separate range for trucks and cars. so, while the first letter in the prefix may be used as a prefix several times, if it is a station wagon letter it will not be used in the truck or car line.

The letter suffixes (second letter) are used throughout the models with no apparent pattern.

We need to consult with the Jeep production manager from 1953/4!!

Chuck - 18 Apr, 12:45 PM

Thank you jyotin, that was very concise. The one theory that the OB vehicles are a pre-production run doesn't quite cut it though since the numbers weren't simply OB11111, OB11112, etc. but rather 11OB5411111, OB115411111, 11111GOB11111, etc. I use these numbers ONLY for illustration purposes in that the OB prefix was not always the first set of stampings on the serial plate. Since these are not completely consecutive stampings, it seems very likely that they came off the line in small batches or groups. Not nessesarily "changed" from a basic 3B but something differentiating them, possibly just a designation prefix for sending them to company X. It seems I remember reading some literature regarding Willys and the Tennessee Valley Authority regarding the use of flatfender jeeps to accomplish much of the mountainous rural electrification that exploded after WWII. They had quite a fleet of jeeps to perform the tasks nessesary. Maybe theirs was a contract "O"rder for the "B"asic platform? They would have been field modified anyway as Willys would NOT have the nessesary equipment to do so themselves. Is this hitting more on all 4 cylinders? I think in the original 3BOB posting that someone thought the OB prefix designated a 6 cylinder...

jyotin - 18 Apr, 04:40 PM

I don't think that the "B" stood for anything unique to a CJ since the "B" as the second alphabetic digit was used on trucks, cars, and station wagons.

I think the "B" was simply the letter B unless we can find some word that begins with a "B" and is common to all Willys product lines including the Willys Lark sedan and yet not common with all other Willys product lines that did not have a "B"

Likewise I don't think that the letter "O" stands for anything except for the letter O.

I do not believe these are intelligent numbers. If so we need to look across all Willys product lines and come up with what words AA,FA,EA,JA, and GB, etc stood for.

It ws the question in the post by Keith Buckley on 17 April that got me thinking about looking at all Willys and not just CJ3b's. His question was What does GB stand for?

I think the answer to Keith's question is simple -- GB is a two letter combination that is not AB or FA or AA or any other willys product line and that's all one needs to know to establish a separate set of serial numbers.

here is a trial balloon on the serial number decode

first digit 4 or 6 identifies # of cylinders second - third 54 identifies year of manufacturer fourth digit A-N Identifies the generic model of jeep CJ, wagon, car fifth and sixth digit ?? identifies sub model within the generic series

remaining digits unique serial number

Which brings us ( or at least me) back to the OB being either a colossal mistake or something that jeep wanted to track separately and later abandoned. If not, then where is 454GB2 10001?

Chuck - 20 Apr, 11:37 AM

Okay, jyotin, I can go with all that except for the OB being a mistake. Since 2A & 3A's also had (apparently) OB designated jeeps along with the "normal" prefix jeeps, there seems to have been a running tally... So, maybe the jeeps came off the line the first of each model year as a sort of test model of the coming "changes" for that particular model year? I also believe that Willys would use those letters as a code for trim, additions, etc. since they were available. Thus, OB may not stand for anything on it's own but might stand for gray seat covers instead of black (as a for instance).I also wonder what part the CJ4 may play in this scenario?

Keith Buckley - 21 Apr, 11:11 AM

The only thing I can say for certain is that the "OB thing is not unique to the CJ3B. I already sent Derek proof there were CJ2A "OB" models, and CJ5,6 OB Models.

Last night I found reference to CJ3A, CJ3B, and CJV35 Models with OB prefix. I also found 1960 references to OB1, OB2, OB3, OB4 models WITHIN each model series.

This is getting aggravating. I wish I knew what OB was for sure!

As an off topic comment, I'm not going to pretend to be an expert, but please do not credit Ford with the M151 design, or 100% of the manufacture. Willys, Ford, Budd, and Fruehauf were involved, just to name a few. Yes, it is true, Ford was awarded the first contracts, and made the most MUTTS, but Willys did make some. The production figures are out on the web. How do I know a little about the MUTT? The M151A2 rear suspension was made by the Highway Products Company in Kent Ohio, about a mile from my house.

When I mentioned that the CJ3B production was moved to make room for the M151 paint line at Willys (on another board) I was smothered with comments regarding how it was a 'Ford' design. (I drive a Ford). Vehicles are designed by people, not companies, and Ford cannot rightfully take credit for 100% of the MUTT.

Al Ray - 21 Apr, 11:54 AM

Just a thought, could "OB" be a jeep that did not pass inspection and had to be sent back through the line. I once took a tour of the mint in Washington D.C. and they re-run the bills that dont pass and put a star in the serial number. Like I said its just anonther thought.

jyotin - 21 Apr, 07:21 PM

I have the serial number tag that I removed from "CJ3BOB54 10982" and the only thing that I can find that was a significant difference from my other two '54 3b"s was a tree that was starting to grow in the rear bed of the "OB" jeep.

The rest of the jeep had been totalled by Ms Nature.

New Postings April-June 2003

Derek Redmond - 23 Apr, 12:51 PM

Further to the discussion of possible CJ-3B production at the Willys plant in California, I have a document which appears to confirm that the California plant was in operation at least into the beginning of the 3B era. It shows production figures for all models made at Toledo and at "WCD" (apparently West Coast Division) from 1949 through 1952. It lists 88 CJ-3Bs made at WCD in 1952.

I did mention this on the old CJML at one point, but I didn't save the discussion because nothing particular came out of it except agreement that WCD probably indicated the west coast plant rather than "Willys Canada." (The document also shows some models built in Canada.)

1949-52 WCD production

In another discussion on CJML in March 2000, Keith Buckley did say, "I went to L.A. earlier this year and drove to the site where the Willys plant was in Maywood. It is now American Velcro. The prefab concrete warehouse spans the entire 10 block area. It was built in the 70's. There is nothing left. I have scoured everything from junk yards to salvage dealers to antique stores. You would never even know it was there except for a few references in books and entries in the old city directory."

The only particular relevance of this to the OB issue, is that the question was raised as to whether the California plant was still in operation when 3B's were in production. This document shows that it was, but unfortunately doesn't prove that it was still operating in 1953 when the OB's were probably produced.

Note: A New York Times article from 24 July 1954 (150K JPEG) indicated that the Maywood CA plant would stop producing Jeeps on 29 July 1954.

Bob W (52cj3a@warwick.net) - 23 Apr, 08:26 PM

Why is the CJ-3A Model listed two times? It shows that 104 and 30150 were made in 1949.

Keith Buckley - 23 Apr, 11:44 PM

I'd be willing to bet that the 104 is actually CJ2A not CJ3A.

Keith Buckley - 24 Apr, 12:32 PM

I believe that document was created well after 1952. I seem to recall it was assembled in 1971 by Coyle Smith in Production Planning.

Incidentally, that whole package was purchased several years ago from the son of the Manager of "Systems and Procedures" for Willys, and later AMC.

As for Maywood, remember it was CKD, so if they knew how to assemble a CJ3A, the switch to CJ3B should have been painless. I also expect you 'could' find that the majority of Maywood vehicles may have been provided to the Transport Motor Company or TMC based in Sacramento. They distributed the whole West Coast with Jeeps and Jeep Farm conversions. I think they had the exclusive rights to West Coast Willys Distribution at that time.

Chuck - 29 Apr, 10:41 PM

Hmmm, identifying tag, eh? Well, I can't vouch for the 3BOB but my '56 has a strange aluminum tag attached to the block on the forward passenger side. I always wondered about this tag (628164) and since running across it the other day, was going to post the question. I am now wondering if I should start scraping all the crud and crap off the 3BOB in order to see what i.d.'s might come out? Is there any concensus on weather or not they had any other type of tags?

Keith - 04 May, 10:24 PM

I'm not sure if I should have started a new topic or respond to this thread since the thread seems to have taken off in a different direction than earlier discussions about specific differences in the BOB's from other 3B's.

I would confirm that the 54OB that I own was one of the first of the line in '54. The transmission has a tag on it dated 10-20-53. I failed to get a photo of it for Derek while it was out. I was on a roll one day and I've been too anxious to get things running. I may still try and get the camera up there and take one.

Also an interesting email was sent to me from Ted Robinette, noticing that the oil pump cover on my engine is similar to those on CJ5's, and not having the flat cover at the bottom as is normally the case. This engine must be the original since the number fits in chronological order. But that's not to say that the oil pump hasn't been replaced from a CJ5 at a later date.

It would be great if other BOB owners would check this feature and respond.

Also I started another topic on the question of a missing snap ring groove on the left front axle on my 54OB. Any others noticed this?

Here is part of the email I recieved from Ted. Ted, If you read this I hope it is fine that I include it. Just trying to help solve the mystery and checking out all the possible angles.

"While browsing F134 engine pix the ones [OB54HepperEngine.jpg 1962BeverFheadLeft9704.jpg ] showing the left side of a CJ5 engine got my attention. I thought I just about had a handle on all the variations in the L134 and F134 engines but the oil pump in these 2 pix proves I still have some to learn.

It looks like CJ5 engines in the 60's had a different oil pump to the CJ2> type that had a flat end cover/plate.

The flat ended pumps replaced the earlier design with a cast end housing used from 1933 to approx 1946. This end casting housed the pressure relief valve and a pivot for the pump rotor.

The later higher volume version had the pressure relief valve in the pump body and used a flat hardened steel end plate. These were made in both alloy and main steel housing versions.

The oil pump shown on the example jpg CJ5 engines has a cast end housing that looks like it also encloses the pressure relief valve. But its main housing and mounting flange [where it meets the block] is different shape to the very early pumps so it is not just a case of a 1933>46 pump being fitted to a later engine.

It may well be that the oil pump fitted to the 2 example CJ5 engines is an aftermarket [Sears etc?] replacement and that is why this shape is not shown in any of the manuals I have."


jyotin - 05 May, 09:56 AM

Keith in another post said that he had OB 10027.

That is interesting....

10027 also has a transmission dated October 20, 1953. That, too is interesting...

Now, if we allow that it would take 45 days to pack, ship, receive, unpack and get the transmission into the Willys manufacturing queue, that would put the cj3b manufacturing date of 10027 in December at the earliest. We could argue the delay time, but it wouldn't be less than 30 days, and that still wouldn't change anything.

So -- if the model year change was in August, what was Willys doing from August to December? It is hard to believe that they could only manufacture 27 jeeps in 4+ months. That would equate to about seven a month. Since they made around 32000 3b's in '54 they would have to produce about 4000 a month beginning in January '54 to hit the 32000 that the records show.

They should have cruised easily into production since the 54 3B and the 53 3B would require no tooling changes.

UNLESS..... there was a 3 month strike at the plant or they made radical changes to the production line and were working out the bugs in the process during those four months.


Chuck - 05 May, 10:14 AM

OR, they came off the line in chunks or batches jyotin. I still wonder about the theory that ALL (OB's) of them were built first before the rest of the 3B's. The reason is the way the OB prefix appeared in the serial number. If they were all built before the regular 3B's then why wouldn't the serial numbers be a consecutive numeration? Instead, there were OBXXXX or XXXOBXXX and so forth. Now Keith has brought up some more tantalizing questions which I can't currently verify since the 3BOB is in the shop. The prior idiot, er owner, tried to chisel and pound the left thread lugs off the wrong way and I was going to swap some wheel/tire combinations around so the question will have to wait till sometime later in the week. Hope I can provide a few answers to those questions and maybe do some more digging after the father-in-law gets over his triple bypass.

Derek Redmond - 07 May, 08:27 AM

Yes, the date October 20, 1953 is certainly another confusing factor. Let's hope we can maybe get some more dates from transmissions, axles, heaters, etc. on more OB's.

Bill Norris - 02 Jun, 10:42 AM

The Detroit Public Library have a wealth of info. I have been able to find the financial reports from 1941 through 1952. That is where I found about about the plant in California. 1952 is the last year they have in the Willys file. I want to see if they have anything in the Kaiser file that might have some info.

Bill Norris - 05 Jun, 02:07 PM

I wasn't able to find too much today unfortunately. Its interesting, in the year end reports for Kaiser, Jeep is just a blip in the document compared to all the industries Kaiser was involved with. Therefore, there isn't near the detail as in the Willys era. Anyway, what I did find may support Jyotin's theory. In 1953 they did post significant losses. 'Significant factors contrbuting to the 1953 loss were declining sales of the automotive industry;loss of production time due to a strike at a key supplier's plant..'

1953 ambulance It does mention that the company is working with the government to develop new Jeeps. One is a ambulance Jeep. It has a picture of the rear of one of these Jeep and it looks like something is attached to the tailgate. Is this a possibility for the different tailgate design?


Owen St.Clair - 13 Jun, 12:12 AM

Been interesting reading on the OB speculation, no expert or even CJ owner here, just want to pop in an idea...about the placement of the OB markings....

Could the reason for the differing locations of the OB stamping placement simply have been different employees doing the stamping on differing days or shifts. IE: Orders come down the line that say mark VIN's with an "OB" so employee Joe put "OB" in the middle, employee Jack put them at the beginning of the other numbers....Just my .02 worth. That might make an impact on discussion of the OB's being built in mass, or in small batches sporadically.

Another thought would be for some research into newspaper accounts of the time period of OB production....looking for public relations announcements of a new contract awarded.... I live near the AM General/Hummer Plant in Indiana, and see this sort of announcement around here all the time. (Headline=Kuwait to purchase 1500 Hummers) It makes our local papers, since it means JOBS here....but rarely is big enough news to play outside of this area. Maybe there will be found an announcement in a local paper from the OB production area hyping the winning of a "new" contract for 2500 "Jeeps". Just an observation, that you guys might not have thought about for a place to look for an answer. Pardon me if my thoughts are too simple, and have already been dismissed by experts. Just figured they were better mentioned, and dismissed again, than missed and found to be significant.

brian hurt - 23 Jun, 03:33 PM

I took the body off (what was left of it) this weekend. I did not find any stampings at all. I checked both right and left on the back and front for the serial # and couldn't find it. Didnt' see the three numbers stamped in a triangle pattern either. Just looking in my service manual at a pic of the frame and it appears I have an extra set of body mounts. Not sure if they are original or added later. 4 sets of mounts on either side, One in front by radiator.

I did find something online on a site that had vin info on it. It claims the 5th spot in the vin # is a zero and the meaning is to disregard that spot. Here's the site for anyone who whats to check it out. http://www.specialtyparts.com/vins/vehilceid.htm

Also, the trans in my jeep is a T90A-1 with a date tag of 7-27-53. The transfer case is a spicer 18. The engine is no help because that was swapped out with a buick 198ci v6

Hope some of this helps.

Chuck - 23 Jun, 06:12 PM

All info is good info. Reading back, I see that I failed to inform the board the fact that the headlight rings are also different on the 3BOB (along with the tailgate). I will try to get a picture in on the rings since I can't explain the difference that well.

Bill Norris - 24 Jun, 01:50 PM

Branham I made it back to the library today and did find something interesting. They have a collection of books called the Branham Automobile Reference Book. I looked at all of the editions from 1953 and 1954. In 53 there is no reference to the OB numbers. The interesting thing is in the May 1954 update they reference the OB numbers as being 'Open' and has a closed range of serial numbers, 54- 10001 to 12600.

The other open body style GB2 starts at 12001 'and up'. So by May 1954 the total number of OBs were built. I took a picture of this page and will send that to you as well. The other interesting thing is they referred to the CJ2As as 'pickup bodies'. The 3A is also, until 1951. It then gets classified as either Stripped chasis or open bodied. Then in 54 the 3B is either stripped chassis, open bodied or farm Jeep. They all have different weights too. They are 1718, 2306 and 2184 pounds respectively. Their list prices are $1,144.65, $1,376.90 and $1,439.30 respectively. Don't know if this helps or hurts, but I think it shows that they were built all in the same time period, pre May 1954.

Mike Winchester - 13 September

In reading the ongoing discussion a thought came to mind: Optional Body? As it seems these Jeeps may have had something unique about them (welder) and was later OB1, OB2, etc., could it have defined a body that was going to have certain optional equipment mounted in/on it, and the later numbers defined which of the optional body configurations it was?

New Postings Sept. - Nov. 2004

Andy Stock - 24 Sep, 11:52 PM

During the discussion on the '54 OB Jeeps I believe someone suggested that there may have been labor or other problems in Toledo, and 3Bs were built on a different line.

Well, I spent a couple hours the other day cleaning the axles of 1954 475-4WD No. 303. The front axle was built on the 16th of November, 1953, and the rear on the 27th. If it takes a month for the axles to be inspected, shipped, and arrive at the Toledo plant, this puts the manufacturing date of No. 303 probably into early January. Willys began model years in August. It seems highly unlikely that it would take four months to build 300 trucks. Also, pretty much every 1954 model, with the exception of the then-new 3B, had abnormally low production figures. So here's my theory: Labor disputes, machinery problems, or something involving the purchase by Kaiser caused a slowdown or shutdown in Toledo. Since the 3B was the newest and highest-volume model, it was being assembled at another location while all other models were not being produced. Whoever assembled these 3Bs marked the serial number plates with "OB" to note the different location. We know 454-GB2 12599 exists, so maybe there was not any intention to build exactly 6000 Jeeps with a different prefix.

Does this make sense to anybody?

Chuck - 27 Sep, 07:57 PM

Yes and no. If all the discussion on the board was related verbatim, there was claims and theory about what you have written. I still contend that an "open body" jeep would not have come to a dealer with a factory installed heater unless the dealer wanted to put the aftermarket optional top on. I think that someone was researching the fact that Kaiser was using up old stock in order for production to continue during aquisition. The claims of incontrovertible evidence that OB stands for open body is not there as claimed, the document claiming California built units never surfaced. Thus, mystery unresolved. Common sense dictates what one will believe.

Andy Stock - 28 Sep, 09:31 PM

I suppose the axle and speedometer dates would be the most surefire way to dig a bit deeper. The last OB without 454-GB2 in the serial number is 12332. However, 454-GB2 AND OB are used on 12211. I don't think OB has much to do with "open body," it just doesn't seem to make sense. If all OBs had the different tailgates, it may not signify a special option package(If it's Option package B, where's Option package A?) but that the tailgates came from a different supplier(overseas?) who did not have the same tooling. All speculation aside, we need axle and speedo dates from the lasst '53s, the OBs, and the first of the non-OB '54s. Who knows what we might find.

By the way, Donaldson air cleaners have a date stamped in them. Do the other models have one too?

Chuck - 29 Sep, 09:16 PM

I thought the dates were not in question. All the date stamp codes from starters, generators, radiators, etc. seem to point to late '53. I don't see what further dating would accomplish. However, any insight into "OB" would be greatly appriciated on this end as I've exhausted avenues of research. All those who piped in with claims of incontrovertible evidence as to their various theories have vanished along with their purported documentation. What is KNOWN is that they had different tailgates, different prefix and were built in the later part of 1953 around the time Kaiser was purchasing the Willys moniker. Good ol 3BOB started life as a brush truck but had the factory heater. I haven't found any evidence suggesting that these "OB's" were special purpose built units but none to the contrary either.

Andy Stock - 30 Sep, 05:19 PM

I wonder if anybody can find a more or less intact stripped chassis '54. If we can find evidence that there were chassis models without 454-GA2 in the serial number, it may narrow a few leads. If OB actually is "Open Body," we should find stripped models with something like NB54("No Body").

I guess with the axle dates I was looking for any strange gap between OBs and non-OBs, or a significant gap at the end of '53.

I don't really have evidence to back this up, It is just my perspective. I believe only the Jeeps themselves can truly answer this question. If only they could talk.

Andy Stock - 29 Oct, 08:39 PM

I was looking through Willys paint chips and noticed that on the 1938 paint chip, there are separate colors listed for West-Coast built and Toledo-built vehicles. Toledo vehicles only had Willys Brown, Willys Gunmetal, and Willys Blue for colors. California-built cars had five different colors. It was a short- lived practice, but it got me thinking. What colors were the OB jeeps? if they had a different color or two, or if some colors were not used, it might say something. This is pure speculation, but it may cut a lead or two.

Chuck - 31 Oct, 10:24 PM

Hey Andy, I can't speak for the others but ours was fire-engine red throughout (ex-brush jeep). This includes the engine.

Andy G. - 02 Nov, 07:48 PM

I believe mine is Island green, OB22

Andy Stock - 26 Nov, 06:38 PM

Well, here's my idea.

For whatever reason, there was a shutdown or slowdown in Toledo in late 1953. The 3B, being the newest model, was Kaiser's bigger concern. Since Jeeps were being produced by overseas manufacturers anyway, they would have one (or more) of them produce 3Bs until work started again in Toledo. The manufacturer, not knowing what the Willys serial number system was, used "OB" as Open Body. When Kaiser-Willys officials found out, they must have assumed OB meant Overseas Built and told the manufacturer to use 454-GB2 and THEN the "OB".

Does this hold water?

Chuck - 27 Nov, 11:00 PM

Hello Andy, the only problem I see with your theory is that the OB units weren't imported, they were built in Toledo. I agree that there was most likely a slowdown during transition from Willys to Kaiser and possibly the change in designation. Every OB I've seen first hand (maybe 4-5) were all specialty built units. The one I have now (which is currently for sale) was a brush jeep, two others were also set up this way and one was a PTO for a threshing machine. There are examples however that are not special units (other than the "OB" moniker and tailgate, etc.) and seem like any other 3B of the time. Just prior, maybe spilling over into the 3B line was the fact that M38's had stopped production (there are some made after on special order) and the M38A1 was beginning. It could very well be that Kaiser was experimenting with farming out some of the smaller production pieces (i.e. the tailgate?)

Andy Stock - 27 Nov, 11:38 PM

So, OB could be "Overseas Built," but referring just to select parts, perhaps the entire body tub? That does make more sense than my idea.

Chuck - 29 Nov, 07:35 PM

They probably had quite a few bodies and associated parts, maybe the tailgate was an item that needed continual production?

Thanks to Keith Hepper and Bill Norris for the photos, and to all the contributors. In particular, Keith Buckley, George Bonta and Chuck Izac have put a good deal of time into researching this question. -- Derek Redmond

See the Surviving CJ-3B Jeeps for the serial and engine numbers of over 1500 Jeeps.

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