Most residential garage door openers have a nylon drive gear prone to fatigue. Over time , the teeth on the main drive gear wear down and completely strip out. Often times you can hear a humming noise from your motor when the gear is broken. Major brands like Chamberlain, Liftmaster and Sears Craftsman have this common gear and sprocket assembly and we stock them on our service vehicles. Call us today if your garage door opener is acting up.