Two or 3 times a year, when I first pull out of the garage, I hear a loud POP. I'm backing out. I think it's related to either recent wash job or high humidity/ rain & probably the parking brake sticking till it breaks loose with a loud POP (rust?) on the 6 speed (Fred). I've never heard it on the automatic (Wilma), but then we never use the parking brake on the automatic. Anyone else experience this occasionally?

Maybe it's just the pads sticking to the rotor till the thin film of rust breaks loose??