Ok.. I've read all the topics on humming rear ends, but I didn't see the symptoms that I am having. There is a head numbing hum coming for the readend that starts out around 30mph and slowly gets louder. But this goes away once I hit 80mph. Also when I let off the gas I hear a "chinging" noise back there as well. This I believe is related to the hum because when I give it a lil gas and the "chinging" goes away and I notice a change in the hum. There is another noise (don't know if this is related) when I reverse. It sounds like a creaking. The noise only happens when I backup and cut the wheel..like backing out of a parking space. In a straight line its fine. I guess to sum up....HELP!! Please.

 

Sounds like you dont have any fluid.. Id try draining it, (if there isn anything in there) and refilling it, dont forget the GM Limited Slip aditive..

Craig

 

I had recently changed the fluid cause of this problem. I checked the fluid level today and it was fine. However when I changed the fluid I didn't put the additive in. Would this cause hum?

 

Without it your limited slip wont grab correctly and will slip. It could be your problem. Easy way to tell is do a burn out and look at your tracks, if its only one tire or one is lighter then the other its slipping.