I need someone in the Philadelphia area who can rebuild my rear diff. Truck has 180K on it and theres a cricking noise when you back up- SOMETIMES! The truck also won't go into drive after backing up- SOMETIMES! I heard that theres a speed sensor in the rear diff that could be failing that won't let the truck go into gear? If I kick off the OD botton it will go into forward and after driving for a bit it will all work normal again. I know the trans might be going too but I want to get the rear done first to see how many of the symptoms are solved first. Does anyone know of a good Ford truck mechanic in the Philly area? I might have him replace the ring and pinion while he's in there too? OR SHOULD I JUST TAKE IT TO THE DEALER?