Chain drive garage door openers have a sprocket that is attached at the top of the motor.
													
																	Garage door chain sprocket replacement. 
									
	
		
	
																	This is a video on how to change the gear sprockets in a craftsman garage door opener. 
																	Located at the top of the motor unit the gear and sprocket assembly drives the chain that opens and closes the garage door. 
																	Amazon s choice for craftsman garage door sprocket replacement for liftmaster 41c4220a gear and sprocket kit fits chamberlain sears craftsman 1 3 and 1 2 hp chain drive models 4 8 out of 5 stars 1 216. 
																	If you replace the sprocket assembly in your chain drive garage door opener yourself you may be able to save a lot of money. 
															
													
									
	
		
	
																	Over time the sprocket s teeth can wear and the chain may jump or skip when the opener raises the door. 
																	This was a craftsman model 139 53976srt. 
																	This diy repair guide explains how to replace the gear and sprocket assembly on a chain drive garage door opener. 
																	This gear kit on amazon. 
															
													
									
	
		
	
																	If the gear and sprocket assembly breaks the motor runs but the door won t move. 
																	The process isn t as hard as you may think so consider the guide below.