If your garage door opener has stopped working (the door will not open or close), chances are the drive gears are stripped. Learn how to replace stripped gears in your Sears Craftsman automatic garage door opener. This may not apply to all models but has some good tips in making the repair. Links on where to get replacement parts and required tools are included.This instructions should be good for a Liftmaster, Chamberlain, Craftsman, Sears, Master Mechanic and Wayne Dalton unit. The model number for the unit in this video are 139.53674SRT2 The part number for the gear set is 41A2817.