My 2008 GXP makes a whining noise when in reverse. Not the normal whine from the helical gears but something else. It only does it for a few seconds when reversing from a complete stop but goes away afterwards. Then if you park the car and put it in reverse it will do it again. Also seems to go away when you turn the wheel in either direction. Sounds like it might be coming from the hubs. Does anyone have any suggestions?

 

Mine whines when you back up when it's at operating temperature. I changed my parking arrangement - when I starting backing into my parking spaces I noticed it.

It happens when I back up straight.

 

I know when the pads are going bad they'll make a screech when in reverse.