I have been having this rearend noise on my 96 rs that nobody can pinpoint..Everytime I put it in reverse and start backing up and turning I hear a "clunk clunk".. I also hear it when i slow down and turn..I've checked the differential fluid, shocks and springs, exhaust and wheels and those arent it..I've had the car for 8 years now with this noise but doesnt seem to affect the driveability of it..I just want the annoying noise to go away!

 

Sounds like maybe a bushing connected to the drive-shaft?

 

Probably your U joints.