I put may 91 max(auto) in reverse and heard a loud mechanical sounding whine coming from the rear passenger tire area. The brakes are squeaking some but this sound is something I never heard before. It stops when I go forward. Any ideas on what this may be and how to fix??

 

I would pull the wheel off and check the rear brakes out..Might need pads....

 

Mine does that if I back up or pull forward with the parking brake barely on. Check the pads/shoes.