Sorry if this has already been posted. I thought I'd relate my recent experience and what I was told about the problem in the hopes it might help someone else.

My 2000 coupe has been making grinding noises during tight low speed turns and clicking noises when taking off from a stop or reversing out of a parking place. I took it in to my trusted (really!) factory Corvette tech and he was advised by GM to replace the diff fluid and additive. This helped a little and only for a short while. I waited a few thousand miles for the noises to get good and loud and brought the car back. The tech checked with GM again and this time he was informed about a new internal technical bulletin (IP ?) for Vette's from 1997 to 2005 with rear end noise caused by the limited slip diff. He was told to replace the clutch pack and refill the diff with NON SYNTHETIC gear oil and limited slip additive, just like the old days. My tech told me to NOT use synthetic oil again in the diff and it would be a good idea to replace the stuff every 15k miles.

My rear end is nice and quiet now (stopped eating the refried beans ) and so is my cars differential.

 

in the old days we used sawdust. :-)