Hi Rick, Does your door have a sprocket?? :-)

As for your gdo, try to put the interruptor cup/rpm boardcircuit back together correctly? Cup all the way onto the motor shaft, and white four prong connector to the rpm board's pins.

Make sure you put the black cap back on the end of the motor shaft and that it is pressed all the way on. Make sure the RPM sensor is plugged in. If neither of these is the issue then you probably did not have the motor shaft pushed all the way back when you tightened the coupler after replacing the worm gear. Loosen that coupler up and from the front of the motor (opposite end in which the coupler is on) push the shaft back as far as it will go. Hold it there while you tighten the coupler back up and then try it.