It sounds like a brake sqeual, but the brakes aren't ingaged at all. I'll be in reverse, not even hitting the gas, and I'll hear it. It's not everytime, but I usually hear it when backing into my garage. Oh, and my garage is NOT at an incline. It's more or less at a decline since the 95' Northridge earthquake. Any suggestions? Also, I do have brake squeal. Any suggestions on getting rid of that?