my 91 rs has problems with it's rear end. It shakes when I'm going around 50 mph. I changed the wheel bearing and the tire still wiggles and only on the back right side cause I switched the rear tires and it's only on that side. when I opened the diff. case I noticed that the case and pinion shaft had grind marks on them. Also the top thrust washer was stuck to the magnet. Has this happened to any one before? I would like to know if a 96 trans am 10 bolt posi unit will fit in my 91 rs? any help will be great thanx.

 

It will fit. But the 4th gen rear is 4" wider overall and your 3rd gen wheels will have the wrong offset.

 

I"m reading around and Ive heard of people putting 4th gen rear ends in 3rd gens, but they use spacers and things i guess. What are these? Sorry to get involved or take over the thread, but i'm just curious. What would he have to do to get it to work and fit with his wheels?

 

Its will be alot easier if you just wait for a nice 3rd gen axle with 373's preferabley.