get the motor& regulator out, seperate motor from regulator, remove cover from gear side, pull gear out and you'll see whats wrong. should be 3 plastic drive pins about 5/16 in diameter but they'll be destroyed, go to your local parts store & buy a gear rebuild kit ($10-$15),regulator will be rivited to door grind the rivits out and when reassembleing use 1/4 pan heads & nuts be sure to Locktite em....