I have read and read threads about all kinds of rear end noise but can't find anything like my problem. I just bought a 1990 Iroc 5.7 TPI 700r4 and a 9 bolt rear. It's in great shape and has been garage kept with 170k miles on all original everything. I am hearing a constant roar from the rear of the car. It's not really loud, just loud enough to irritate the heck out of me. It sounds about like the roar of a good set of all terrain tires. I thought it was the 13 year old tires so I changed them and it didn't help. I also changed the differential oil and it didn't help. There was absolutely no metal in the differential, not even tiny metal slivers in the old fluid. There was no wear on the ring gear that I could see or feel. It's constant at all speeds, maybe slightly louder when I barely touch the gas when just coasting. Any ideas on what my problem might be? Is some noise from the rear normal? I haven't had a third gen in 15 years but don't remember it in any of the other cars I had.

 

U-Joints ? I had a similar problem, switched to a low mile 2002 ls1 aluminum shaft and that hum went away in mine, smooth as ice, but at 170k many items to be wary of...

 

Thanks. I should have thought to check that when I changed the diff oil. Anyone have anything else that I could look for while I'm under there checking the u joints this evening? I just want to check all the things that I can before I put it in the shop if it's not u joints. I forgot to mention that I already put new brakes on too. Thanks

 

Bearings, but you probably already suspected that. Most roaring noise comes from a bad bearing.

 

Yeah I figured it's probably bearings. I just want to make sure it's not something that is an easy fix that I can do myself before I put it in the shop. I just got it and hate to send it to the shop for a couple weeks.

 

Sounds from the description like the wheel bearings.

It's all easy. It's just a car, after all. Coming up with the right parts is the least easy part, particularly the seals, but beyond that, pretty routine stuff.

Not sure what that is... or if it's even possible to attempt to hot-rod an antique car, but would have to do that?

 

Thanks. I don't understand some of what you said but thanks. Maybe it's just wheel bearings.