squeaking noise from rear only when backing up

Well the title mostly says it all. I have a 2002 camaro z28 A4 and there is a squeaking noise from the rear, but only when I am backing up. Has anyone else had this problem or know a fix? It's quite annoying.

Thats a hard one. Personaly never happen to me, but brakes maybe?

I think the best way to describe it is when you open a squeeky door on a house, almost sounds just like that. I was thinking maybe it is some bushings or something that need to be greased or the shocks or springs? It's not like squealing brakes though. Should have been more descriptive first time around.

It might be worth checking your spare tire and jack. After I used my spare I did a sloppy job of re-stowing that stuff, and it made all kinds of weird noises. If the tire is loose it can squeak, and if the jack is loose it can clank around.