My car sat for about six years without moving. It only has about 20K miles on it (from sitting allot). Before driving it, I changed the oil in the rear. Stuff looked ok, but there was some mild surface rust on the carrier, caps, cover, all above the oil line (it's really humid in houston). The magnet had allot of fine metal grit attached to it. I cleaned it up as best I could and figured I'd drive it a few miles and then change the oil again. Upon driving I noticed some noise off and on sounding like it was coming from the right rear area.

I drove it about 100 miles (several short trips and a couple of longish ones of about 20 miles. I thought it might be wheel bearings so I decided to change them out. It's hard to tell with this stuff since I'm paranoid, the car sat for a long time, and now it has no carpet or rear seats in it so the interior noise is real different from the way I barely remember, so this might all be nothing.

I pulled the cover, no real accumulation of new metal on the magnet. That seemed good. Running did seem to clean up the majority of the rust. After pulling the axles and rear bearings, it didn't seem like anything was wrong with them. However, I was suspicious of the rest of the rearend bearings so I pulled the carrier out.

There were no side to side shims, only the two thick spacers, but it seemed plenty snug enough in there. The passengers side race and bearings gave we a little worry. Here is a pic of the race complete with what appears to be some heat marking:
http://i55.photobucket.com/albums/g1...t/DSC01303.jpg
Here is the worst marked bearing:
http://i55.photobucket.com/albums/g1...t/DSC01302.jpg
Should I replace the carrier bearings and races? If I do, will it affect the side-to-side shimming of the carrier?

Another thing that is bothering me is the way this looks:
http://i55.photobucket.com/albums/g1...t/DSC01304.jpg
http://i55.photobucket.com/albums/g1...t/DSC01305.jpg

See how the passenger side axle gear sits in a race or cup of some kind, is this the mysterious cone clutch itself? Was this race just simply misaligned when it was pressed in, or has the side gear spun it inside the carrier some how? Is this something to worry about? These carriers are "non serviceable" so I can't really take it apart to see if the "cone clutches" or whatever looks damaged or scored.

 

What kind and weight oil do you use?
If it's a (9-bolt) limited slip, did you use the GM additive?

 

Funny you should ask. When I bought the car brand new, it had sat on a dealer lot for almost a year. The first time I drove the car out of town, it was chattering on turns when I got to the destination. After cooling down, it was fine. The dealership changed the lube out and said that the additive had seperated from the oil. This made it chatter when hot and no harm was done so they said. They cleaned it out, filled with new oil and additive and sent me on my way. About a year later, it's doing it again; opened it up and like before the additive is now a goop adhered to the inside of the housing. This time I replaced it with some Pennzoil gear lube(i think) that needed no additive for limited slip applications. Amazingly enough it never chattered again even after long spells of sitting.

Should I be looking for another rearend? It's a 10-bolt with disc brakes.

 

My 9 bolt L.S. Borg Warner rear makes some noise as well, only when cruising at about 55 mls, I don't worry about it, as long as it doesn't get worse.
I use Castrol Synthetic axle oil, 75W140, with a bottle of GM additive.

 

Cleaned all the crud out of the axle tubes and put it all back together with new wheel bearings and seals. I didn't change the carrier bearings or races. Filled it up with Castrol dino-oil mixed with the limited-slip additive. Ran it on the jack stands in forward and reverse for a few minutes, mostly forward hoping to lube up the axles and new bearings good. Every thing sounded real quiet so I let the car down and drove it for about 10 miles. No chattering in turns and fairly quiet back there compared to before. I can hear the brake pads dragging now, and it's not like they make allot of noise. So I'm guessing the lack of an interior magnifies all the noises to ridiculous levels. I have the factory spring pads installed so I can only imagine how noisy the inside would be without them.

 

how'd the axle bearings look? were you able to isolate the noise before removal?

I have either a bad axle bearing, or the preload is gone on my gears. hope its the axle...