On my 87 Vette conv't, every once in a while, while backing up, I can hear a "rubbing" noise in the area of the left rear wheel. My mechanic has taken apart the whole rear wheel, brakes, etc and has found everything to be in tip-top shape. There are no rub marks inside the wheel well, and no "contact" marks. Does this sound like it could be the wheel bearing starting to break down.

mypetu39

 

Could be, also check u-joints in half shafts and drive shaft. A dry joint can sound similar to "rubbing" noise.

 

I've noticed the same thing. I'm a new owner of a '94. I think it must be some system getting preset (ABS maybe). Like cocking the hammer on a gun to get ready to fire. It does it consitantly and only the first time I back up after starting. I have not identified the cause, but I don't think I'll be paying anyone to tell me my car's OK...thanks to you.