We back our LS into the garage. The driveway has a decent slope. While backing up the slope, we hear a grinding noise that seems to be coming from the rear. I have completely replaced rear brakes and there is no change to the sound. There is no wheel bearing noise. It is not related to the emergency brake. I can not replicate the noise while backing up on flat terrain or hear anything while going forward.

I can't find anything rubbing or see anything abnormal from underneath. Transmission is smooth as silk. Rear differential?????

I keep telling my wife that it will get worse and reveal itself, but this continues.... Ideas? I'm not small enough to have her back over me in the driveway!!!!

 

Completely replaced rear brakes- did this include brake shoes inside the drum and associated hardware?
The E brake self adjusts when the (foot) brake is applied when driving in reverse. If your brake shoes (not the pads) are original to the car they are likely worn and rusty. The self-adjusting process could be noisy.

 

Yep. If you never used it and god forbid parked outside a bunch it may actually seize up but not very likely on an LS vs other cars. I use mine every single time I park before I let the main brakes down so the parking brake is responsible for the vehicle weight not the trans prawl

 

any chance a backing plate got bent during the install? Was this sound present prior to the brake job, or appeared afterwards?

 

The sound was present before and after the brake job. The first thing I suspected was the emergency brake and self adjustment. We use the emergency brake often and the car is parked in the garage. There was no corrosion and little wear on the emergency brake shoes when I changed the pads and rotor. I've backed up the driveway with the emergency brake applied slightly and it does not affect the sound. The sound does not seem to be brake related.

 

driveshaft related would be my guess because reversing uphill loads the suspension and driveshaft differently than flat ground

 

Thank you. I will poke around. Change fluid, etc.