i was told there is a bushing/bearing in the T56 where the driveshaft slides in that could wear out and cause vibration.

anyone have a part number or know what its real name is?

 

Are you talking about the dirt seal? If so it's easy to replace. just slide old one off, go to parts store with $5, slide new one on. I don't think that it could cause vibration though. TTT for ya

 

nah thats not it........i had my driveshaft balanced, and found out it had been shortened (probably by someone who had a 12 bolt rear). so it wasnt inserting all the way into the tranny, and they think spinning like that for 1-2 years has done damage to a bearing or something thats in the end of the tranny. the shaft itself is in good balance.
just in case anyone suggests it, my tires and wheels have been balanced also, as well as trying 2 different sets.

 

the yoke on the driveshaft just splines on the output shaft of the tranny. there is a bearing on the output shaft of the tranny. it is about 50 bucks from gm and that is the only place i could find it. it is plastic and the race is actually in the tranny case but i have not heard of that going bad. mine went bad because i snapped my driveshaft in half and the front part of the ds got hung up on my subframes and ripped the tailshaft of the trans its self. but i have not heard of this bearing going out on its own.

 

can you change it without taking the tranny out/apart?

 

i dont think so. even if it was humanly possible i wouldnt try it. you would have to pull the tailshaft off of the tranny. if the tranny is out then it is not hard at all. just take the bolts out of the tailshaft and take out some roll pins and some snap-rings and its right there.

 

There most certainly is a press fit bearing (actually a bushing) in the tailhousing of a T56. It is located right in front of the the seal/dust excluder in the tail. If the bushing is worn out of round, it will absolutely add to your driveshaft vibration problems. I've been there. You can buy a replacement bushing from D&D. To replace the bushing, youl'll have to remove the trany. Then, remove the tailhousing. You'll need a press with the correct size adaptors.

PS I wouldn't even try to do this in the car

Steve