Swapping Warn overdrive vehicle to vehicle

I did a search and didn't find anything on this question. I have a friend that is selling a '44 Willys MB with an overdrive. I talked him into selling me the overdrive to install in my '50 CJ3A. Both have T-18 transfer cases, but is there a difference in WW2 and post-war t-cases? What do I need remove from the '50 to install in the '44 if it's possible. My concern is tooth and spline counts for the trans output.

 

If the MB still has the original D18, it will not work. The MB/GPW's use a 27 tooth drive gear where 3A should be a 26 tooth. You could possibly do a trade with Herm (the overdrive guy) and get the 26 tooth bowl gear for the OD. I would check the teeth count on both before you do anything. A lot can get changed in 60 some years. Are both cases 3/4" diameter intermediate gear shafts?-something easy to check.

 

Why won't the front shift work on a 3A? Should be the same as a 2A. front shift wont work on a large hole transfercase I thought? 2A, 3A, 3B all are 1 1/8" shaft 26 tooth 6 spline.

 

Only partially true. Not sure when the exact change-over was, but sometime within the first 2 years of production, the 3B got the same case as the CJ5 with 1.25" intermediate shaft and 29 tooth drive gear. My 55 came with a 29 tooth gear. I also can not think of any reason why a front shift OD will not work with these cases-all essentially identical on outside dimensions.

 

The large hole 20 style cases (with the two shift rail caps on the back vs. casting) has a "hump" cast as part of the case where the shift rod for the overdrive needs to go whereas the 18 style case does not have this hump. Hence the front shift overdrive won't fit on a 20 style case but will on the 18 style case.

 

Thanks for the responses. I'm pulling it tomorrow to see what he has and will update.

 

True, who the heck knows what is in a Jeep after all these years! mehh There aren't all the same as I found out. there's more then two variations as well. I wasn't trying to argue with you just trying to add more info. I had 4 of them on the bench a few weeks ago trying to get one up and running and they where all slightly diff, and not interchangeable as far as internal parts. There's early ones that have a small rear bearing verses the later large rear bearing etc. the shaft is diff slightly on the two as well plus other diff.

 

Pulled the trans output gear off the 3A, 26 tooth 6spline. Heading over to my buddy's to pull the OD.

 

Found that the Warn overdrive I pulled out is a 29 tooth 6 spline. Everything looks in good shape. To put this in my 3A do i just need to change the bowl gear to a 26 tooth? I also need to find a 29 tooth trans output gear to get the MB driveable.

 

All the gears are different between a 26 tooth and 29 tooth 18 transfer case. I'd upgrade to a 29 tooth personally. Slightly stronger and slightly quieter (more teeth in contact). Plus more needle bearings and larger intermediate intermediate shaft. You can put the 29 tooth gears in a 26 tooth case (1 1/4" intermediate shaft with the 29 tooth vs. 1 1/8" in the 26 tooth) but I'd recommend upgrading so you get more intermediate bearings (quieter, stronger due to load distribution, etc.).

 

I'm going to leave the 26 tooth gears in the t-case. I just rebuilt it this summer. I posted in classifieds to find the parts. If no responses I'll get in touch with Herm. Could use a 29 tooth trans output gear cheap though. Got to get my friends jeep rolling, he's selling it.

 

I scored a Warn Overdrive from a Willys truck as well as the tranny and T case. The tooth count was wrong to use on the CJ2A. But someone on the CJ2A forum explained to me that the Willys truck T case would bolt right up to the CJ2A tranny. So, I have a CJ2A tranny with a willys truck T case and OD.

 

Update, just got my Xmas present installed in the 3A. Sent it to Herm for swap of the bowl gear and complete rebuild. Had to modify the shifter (back to original) but everything bolted up and works great. BTW the OD was a rear shift.