Let's Talk T18 and T98

Pretty sure thin bearing is same on the front. Mine was listed at 20mm, not sure what is the comparable SAE size. Rear bearing is thicker in the back on the later Jeep models. Mine was listed at 23mm. Might have something to do with the position of reverse; mine is down to the right. I think Furds were same front and back. I think T-98 was same front and back. I'd link the reference I used to order bearings, but it apparently is not working now, so this is all from memory, YMMV, IMHO, and all that jazz.

 

Dan,

Would it be worth getting a T18 core to be able to look at it in it's entirety? Might eliminate and chance of using the wrong bearings if you have something to start with that is complete. I have never seen the t98 case. Is it different from the t18 case that you couldn't use the t18 case with your adapters front bearing reatainer etc?



Todd

 

My '79 Jeep T-18 is definitely different than the T-98.

 

I agree, but I was speaking directly to your comment about the cases themselves; they are definitely different. There are differences in the input shafts and retainers, too. I think you can swap an entire assembly from one case to another, but I don't think every part is interchangeable within those assemblies. My front bearing retainer was a lot different and had rifling on the inside for lube. I could not swap my Jeep retainer onto a Furd input shaft because there was a bushing on the Furd with no recess on the Jeep retainer for it to ride.

Here is a shot of the driver's side of the two cases. I believe the differences are due to the reverse gear. I don't think the shift covers are compatible, and might possibly make the reverse idler, shaft, and bearings incompatible. I think we all need to pitch in and get Nickmil some dish internet:


Note the bulge where the T-18 is flat:

 

Mine is a wide ratio; big ol' honkin' straight-cut, non-synchronized first and reverse. It's a '79+ model; shifts over and down. Don't know all the internal differences as I never had a T-98 assembly to directly compare. Same one is pictured on the Novak site:
http://www.novak-adapt.com/knowledge/t18_t19.htm

It does stick out farther than what that picture might show from a side shot, but it extends all the way up to the shift cover, whereas the T-98 is just a small bulge down at the bottom:

 

It sounds like you hit the same snag I did. Take a look at the pics and see if the gap is similar to yours. Click here

nickmil helped me out on this one. The front bearing required was the wider (I think 23mm) bearing but it would not fit with the oil baffle I had so I installed the narrower (20mm I think) bearing. This caused the gap in the picture and it would not stay in 4th gear. I ended up removing the oil baffle and using the wider bearing and all worked great. I think the oil baffle only resides in the older version transmissions (pre '79 I think).

Hope this helps.

 

Dan, what is the orange stuff in the bottom of your tranny?

 

I can't seem to locate the receipt at the moment from partsmike but I have it around somewhere. It's probably quicker to give Mike a call at http://www.partsmike.com. There are only two front bearings for the T18, the difference being one is wider than the other. Tell him you need the wider and he will know what you are talking about. You might even mention the name Bryan as he might remember me since I bought the short shaft kit and many more parts from him. (Maybe I'll get a discount next time I order).

I see you still have the oil baffle installed. I would go ahead and try using it with the wider bearing. However, if the snap ring lacks the width of the oil baffle from installing, you will have to do away with it as I did. Apparently the short input replacement shafts are modeled after the '78 vintage which did not use the baffle.

You might want to give your pilot bushing a good look since the input shaft was floating in it. Mike also sells this if you need another.

 

I drove it home from the driveline shop and around the block a few times trying to troubleshoot the problem. In doing so, I found that the input shaft was rubbing against the bearing retainer (nose cone I like to call it) when I got it back apart. It also created a bur on the case where the front seal resides so I had to file it down. If you have any doubt that the front seal will not seal, go ahead and replace it too. Again, Mike sells all this. I was lucky enough to reuse what I had.

As for the bearings, you should be good to go. Just make sure you get a good seal on the input shaft and replace anything suspect. Those tranny's are heavy and I don't like pulling them.