An online search revealed these gear motors fail a lot in microwaves. Pulled the microwave from the cabinet (its a built in unit) and found they had thought ahead and pre-punched an access panel into the bottom. The old motor was not labeled, but they all are pretty much the same, and this one looked just like it. One simple phillips screw and the replacement was in place - literally a 2 minute job. Works like a champ now.