Posted: Mon Jun 20, 2016 1:38 am Post subject: Transmission rebuild question
Doing a full resto on my 64 mc a1. A lot is/has been needed, and surprising some things you would think would need work, don't. I pulled the transmission and transfer. I opened them both up, and they both are shinny and good looking. After adding lube, the transmission shifted fine, even with engine running. Unknown at the time though, the output gear in the transfer was stolen off it.(No wonder why i could never get it to drive ) My questions is : Is there any way or obvious signs to tell if it needs a rebuild ?. Like i said, it shifts fine, and is like new looking inside. The reverse idler gear COULD be replaced, it has a bit of wear. The rest of the gears just show some wear. None of the teeth stick out as rq replacement. The jeep sat for 15 years, but started up fine and shifted after just a little elbow grease. Only has 5,558 miles on it.
Joined: Mar 26, 2012 Posts: 189 Location: Lexington Park Maryland (Southern Maryland)
Posted: Mon Jun 20, 2016 6:27 am Post subject:
Detailed pictures would help the experts here take a look at what you have and give you a better answer.
If you are doing a full restoration of the jeep in my honest opinion you should take them out and do a full disassembly and inspection. I just finished rebuilding my tranny and TC and it was not hard. When I opened up both of mine they look fine with some wear and everything worked fine before I started the restoration. However as I started to inspect everything after disassembly I started to find things you cant see during a visual inspection. For example within my TC the bushing that is pressed into the output shaft for the output clutch shaft was out of tolerance. Also I found in transmission that the main shaft pilot shaft was worn out of tolerance when inserted in the main drive gear. If this fit is loose it will cause excessive wear on the engine crankshaft pilot bushing. That's just two examples.
So long story short in my honest opinion you are better off taking everything out, inspecting, replacing where necessary, and rebuilding with new seals, gaskets etc. Its a peace of mind thing for me. I know that everything is good to go now and when I have the jeep complete I wont have to deal with a potential failure after completing the restoration. The guides below were very helpful and go through inspections of all the components as well as the TMs for the correct tolerances and many other resources available online
The above is good advice. There are only two ways to make a reasonable evaluation of the condition of the tranny and transfer.
1 - The best choice is a complete teardown inspection and dimensional check.
2 - The second choice is to operate them at all normal speed ranges under all normal loads throughout all gear ranges.
This is why I always advise new project owners to get her running first and drive it to evaluate all systems and compile an accurate list of what needs work.
Whenever you think you might skip an restoration step always take a hard look at how much work you will be facing if you made the wrong choice on an item or system. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Ya, wes, i wish i could of driven it, just like said, no output gear in transfer. So no motion . I guess i will be rebuilding it. I was worried about the seals being so old, and reverse idler really bugs me. I'm just not a tranny guy and don't know any who are, very leery, heard horror storys with all the tolerances.
Saberr, I can tell you---you are over thinking it!! The T-90 is about as simple as it gets. Just pay attention, take pictures and lay everything out in order. Read the manual on how to install all the roller bearings in the cluster gear and be prepared to do it a couple of times and next thing you know, you got it!! After the first one, you are an expert!!
Like the other have said--the least you want to do is replace seals, gaskets and all the small parts (there is a small parts kit you can buy with all the rollers bearings, bronze washers etc in it). As you just don't know how it was treated before hand.
If there is more then 3/4 of the reverse gear teeth on the gear, and it is tight on the shaft, I would just de-bur the edges of the teeth and go with it. The burs are there from grinding it into reverse. However, these gears are not that expensive. You also want to check the gear that meshes with the reverse gear as it may be blunted also. Lastly, check the teeth on the synchronize, they should have plenty of tooth left on the steel teeth and might as well replace the brass synchros while you are there. They are prone to wear from heavy handed down shifting. _________________ Harold W.
MVPA #6833
1945 GPW
1950 CJV-35/U
1951 M38 1952 M38
1962 USMC Contract M38A1
1953 Strick M100 1967 Johnson M416
1968 CJ5 4-Speed 1969 CJ5 V6
Surprisingly, no burrs on any of the teeth, just a bit of blunting on reverse idler. Syncro has a little blunting as well. This is a rebuilt tranny at one time, tag still on it lol. But at last seals don't hold like steel and brass parts. Taking parts out to do seal, might as well do all.
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) My questions is : Is there any way or obvious signs to tell if it needs a rebuild ?. Like i said, it shifts fine, and is like new looking inside. The reverse idler gear COULD be replaced, it has a bit of wear. The rest of the gears just show some wear. None of the teeth stick out as rq replacement. The jeep sat for 15 years, but started up fine and shifted after just a little elbow grease. Only has 5,558 miles on it.
. I guess i will be rebuilding it. I was worried about the seals being so old, and reverse idler really bugs me. I'm just not a tranny guy and don't know any who are, very leery, heard horror storys with all the tolerances.
