Have a 98 Z28 with 14800 miles. Owned it for 11 years. Purchased it with 4000 miles. Had rearend fluid changed at 6000 miles by the chev dealer. Has been making a creeking noise when you turn to the left or the right for the past 7 years. Drive it only 1000 miles a year, no rain or snow ever. Any suggestions?

 

98 was the last year for the Auburn differential. It requires limited slip additive in the gear oil. The 99-02 cars got a Torsen diff, which does not require limited slip additive. It's possible the dealer neglected to include the limited slip additive. And if that's the case, the differential is now junk.

 

Why did they change the diff oil at 6k?

 

Not an engine question. Moving to drivetrain.