Just had my transmission rebuilt by a friend who is a Ford certified tranny specialist. The tranny goes from 1st to 2nd just fine, either when accelerating slowly or quickly. However, if you are in traffic and start to move, but you have to back off the gas before the tranny upshifts from 1st to 2nd,you sometimes get a clunking sound. This only happens when you have to back off on the throttle at low speeds. Any ideas? It almost sounds like something wrong with something in the electronics,or something along those lines, rather than a gearing problem. Any help is greatly appreciated.Thanks