T90 TRANS

[Macgraham]

I have run into a problem because of my lack of knowledge putting my t90 back together. Both roller bearings have snap ring grooves and my trans. will not fit flush to the transfercase with a snap ring installed.  What am I doing wrong? I have it apart again trying to figure it out. If there is not supposed to be a snapring on the rear bearing it looks like it would fit ok. I think there must be a reason for the groove in the new bearings. Help!

[Ryan_M]

have you checked out the T-90 rebuild guide on this site?

http://www.cj-3a.com/T-90%20Rebuild.htm

I am a mechanical idiot and had never seen the inside of a T-90 or any other transmission prior to this project. I completely rebuilt my T-90 solely by following this guide step-by-step. Maybe read through it and see if you installed one of your components incorrectly?

[Carls_jeep]

The rear main bearing should not have a snap ring, nor should it have a snap ring groove. You may have the wrong rear bearing.

[calvinhunt]

Macgraham,

Carljeep is right. �You may have two input shaft (main drive gear) bearings. �The rear bearing does not have a groove for a snap ring. �I don't remember them even being the same size. �It's been too long since I was in there. �If they are the same size a ring groove wouldn't hurt anything (if you leave the snap ring off). �If they are different sizes, of course, you'll have to get the right one. �

Besides the on-line guide suggested by Ryan_M, I really like the one from Novak Conversions:
http://www.novak-adapt.com/knowledge/t90_rebuild.htm

I had both guides printed off and in front of me during my overhaul. �I had never touched a tranny prior. �I believe it took both of them to help me understand what was really supposed to take place. �It worked. �Let us know how it goes. �Good Luck!!

[3aJeeper]

Ryan/Calvin,

Not having done a trans rebuild before, how long did it take you to complete it using the guides? Is this an afternoon type thing or a few days? Debating if I should crawl through mine and want to get an idea of duration. I want to be able to do it in one session. I don't think I want to take it apart and leave things lying around for a few days before getting back to it. Even with taking pictures and the guides I'll forget something....

[Carls_jeep]

IF, you have all the parts, and that is hard to do until it's torn down, you could do it all in one or two days. However, many times you will find some parts inside that need replacing that you didn't order. I suggest you tear in down one weekend, inspect and measure and order what you need and when the parts come in build it the next open weekend.

My opinion is, this is not something you want to rush through and there is no way you can know every part you will need. You may want to write notes as you tear in apart so you know what you did and where things go but the articles linked cover a great deal of info.

Also, buy NOS or American made parts ONLY. Do Not buy parts made overseas.

[3aJeeper]

Carl - Good points I'll need to ponder, but you're right - likely don't know what I need until I get it apart.

[Macgraham]

The rebuild was not a problem as long as you understand how the needle bearings go and use heavy grease to hold them in place. What threw me off is the groove in the rear bearing. I bought the bearing and seal kit from Kiaser Willys. The bearings seem to be the same size and the ones that came out of the trans both had grooves. It just messed with my mind cause I thought if there is a groove it must be for a snapring. I will check with Kiaser and see if they can smarten me up. Thanks all for you're help.

[Ryan_M]

Ryan/Calvin,

Not having done a trans rebuild before, how long did it take you to complete it using the guides? Is this an afternoon type thing or a few days? Debating if I should crawl through mine and want to get an idea of duration. I want to be able to do it in one session. I don't think I want to take it apart and leave things lying around for a few days before getting back to it. Even with taking pictures and the guides I'll forget something....

I tore mine apart only because when I removed the TC for the first time I didn't realize that I had to secure the transmission innards or else roller bearings would fall all over the place - and they sure did. So I took it apart, realized I needed more parts than what I had on hand, and it was a week or two before I got it back to it. By then, I had hopelessly forgotten how everything was supposed to go. BUT, following that rebuild guide was a cinch. The custom made "tools" that need to be created at the start of the guide were lifesavers. As was having the correct transmission assembly grease on hand. I also took tons of pics BEFORE I ripped it apart so I had extra reference material. The rebuild took the better part of the afternoon/evening but as mentioned earlier, I'm anything but a mechanic. The entire project could have been done in a day if I had all the replacement parts on hand right from the start.

[Macgraham]

Well I got it all back together and when I bolted it to the transfer case it would not turn no how! Now it is all in pieces again and I have ordered parts that I hadn't planned on replaceing this time. I think I've got it figured out but if I have to take it apart too many more times it just may make it to the Colorado river!! looking like a pretty good anchor.

[Carls_jeep]

Something is assembled wrong but I guess you know that. The best way to see if anything is binding in the tranny is to use the old rear bearing that is honed out so it slips easily on the output shaft. Then assemble everything and clamp the rear bearing to the rear of the tranny housing. You should be able to move the shaft forward and back about .010" to .020". If it has to much end play you need a thicker spacer or some shims and if it's to tight you need a thinner spacer. The spacer goes in front of the rear bearing. If it has to much end play it will probably jump out of second gear. If it doesn't have any end play you may burn up bearings and shafts.

I had to machine a new spacer for my tranny to get things just right.

[Williamsmar]

I have a pretty good leak at the tranny bell housing.  I know its the seal but would a small parts kit and gasket kit fix my problem.  It shifts fine doesn't seem to have any issues other than the leak.

Thanks,

Marty

[Carls_jeep]

If your sure it is tranny oil rather than engine oil then the input shaft seal is worn out. The seal is a felt ring with a rubber washer on one side. You have to soak the felt seal in oil for an hour or so before installing it.

You have to pull the trann/transfer cases and pull the throw out bearing and front bearing retainer. The seal goes on the input shaft and I think the rubber goes toward the bearing but you need to look that up.