aa7kn

Ok here is what I have, I have a 1991 XJ 4.0 AX15 5 speed, I had a bad trsnsmission mount so I got a new one from the dealer, I installed it, and I noticed it was a little bit taller than the old bad one, but I just figured the old one was soft and compressed. But now I have a vibration upon accelerating and slowing down, I feel it any time the jeep is under power. I noticed that the drive shaft is not straight into the back of the tranni, the tail shaft is straight, but the ujoint has to angle down, also the yoke moves from side to side inside the tail cone a little, is this normal? Could this be a case of a to tall tranny mount making the drive shaft out if alignnent and or a bad tail shaft bearing or both ? I tried finding info on this but couldnt so please excuse me if this is a repeat thred. Hope someone has some input on this for me. Thank you

cruiser54

Could be. Could also be that your engine mounts are pretty worn also.
No leak from the rear of the transmission/transfer case?

salad

Is this a 2WD or 4WD? 1991 2WD might have a greaseable slip yoke. That said it's not uncommon for the final output bearing of a transfer case or transmission to get worn and cause that. You'll have to remove the drive shaft and check the output on whatever you have. There should be NO play.

The U joint is supposed to be angled down, by the way.

freegdr

Stock height or lifted and what lift ?

aa7kn

this is a 4WD stock everything...I was looking on line and maybe the dude at the dealer gave me a mount for an automatic....I saw an article about changing the mount on an automatic, and the mount the guy in the article had looks just exactly like the one I got from the dealer...so I think I have the wrong mount. is that possible ? will the automatic mount fit in the manual AX-15 ? it is a lot taller for sure....and no, there are no leaks from the tranny output tail seal, all is good, just sits to high in the back....I am worried about the angle the yoke U-Joint has to operate at, it is noticeable but not very much, but I think with a shorter mount, it will be straight....what do you all think ?

cruiser54

I'm thinking you're on the right track. The mount attaches to the adapter housing between the trans and transfer case so I'm guessing the pattern is the same between the 2.

aa7kn

well I found a short " Correct" tranny mount at a local Jeep Junk Yard still in real good shape. I installed it and wow, what a difference....the one I had that the jeep dealer gave me was for an automatic, just like I thought, I put in the one I found and it dropped the tail of the tranny about 2", giving plenty of clearance between the tranny and the body, and also pretty much straightened out the alignment between the tranny and the rear diff, so the drive shaft is almost straight...no more rattles, and no more strange noises.....so the bottom line is, that an automatic transmission mount will mount to a 5 speed tranny, but it is to tall and will cause the tranny to rattle up against the car body and make the angle pretty extreme between the tail of the tranny and the rear diff...it will work in a pinch, but the correct one is always your best bet...thanks guys...maybe this info will help some one that might have the same problem, thanks for your input....