When overdrive kicks in, in my auto Jimmy, I hear a grinding sort of sound. It usually occurs between 40mph-50mph. Any suggestions on what it might be? I read in Peterson's that someone put Rhino on the outside if the truck. I think this is a good idea. Probably use herc or something cheaper. How much prep needs to be done. Just take the wax off? The paint? I heard it sticks to anything, so if I just roughed up the surface would it work with out stripping it?