have been hearing a kind of a dull grinding noise in the rear of my 04Z .but only on tight U turns . Took car in to dealer and after 2 days they said they changed the rear end fluid and it would take a few hundred miles to work in. but noise is worse and louder. Almost sounds like tire is rubbing on somthing. car is lowered about 3/4 inch on stock wheels and tires . any ideas ? thanks

 

I `m was having the same problem but I replies the rear ball baring and the sound stopped

 

Sounds like the differential clutches. Did they use additive?? That quieted mine for a while but have to get the clutches replaced next week. It is warrantied.

 

Just had the entire diff rebuilt by the dealer (thank you GMPP) for the same noise.

 

i have the same noise i was wondering what that was...what should i do... i have a 04 coupe

 

Try Beano.

just couldn't help myself. LOL
jeff

 

My C5 is at the dealer now for the same noise so far they have change bearing and one axel and noise is still there. could this be a factory defect?

 

I had the leak (L/H) repaired at 20K miles. Around 35K I noticed a grinding noise when turning a tight circle, left or right. I thought perhaps it was the clutch packs, maybe they didn't add any friction modifier to the rear end lube. At 40K it started getting much worse. I took it back to the dealer and they removed the rear end and found the pinion and L/H side carrier bearings badly galled. GMPP paid for a new rear end installation. Evidently it was more cost effective that rebuilding the old one. It's very quiet now

 

should i see if they will put a new rear in my coupe...could that be the problem?