The shifter for the M45-46 transmission has a ball at the bottom of the shifter stick. On the top and on the bottom of this ball is a plastic (nylon?) cup that encases the ball and provides for a slipperly surface for the shifter ball. The top piece of plastic slips easily off the stick after removing a retaining ring. The bottom piece of plastic seems to be "trapped" between the bottom of the shifter ball and a ring that connects to the transmission shifting link. This ring is bigger than the hole in the plastic cup. The question is, how do you replace this piece of plastic or is it even replaceable? Any help would be appreciated.