The gear and sprocket assembly is inside the cover of the garage door opener motor.
Garage door chain gear broke.
A new garage door open start around 130 00 plus installation.
Lay the chain on the garage floor while you complete the repair.
Remove the outer nut and lock washer from the trolley threaded shaft and pull the threaded shaft out of the trolley.
The gear will cost about 50 00 with shipping and then the cost of having someone install it.
Move the ladder to the outer end of the chain arm near the garage door.
How to lubricate a liftmaster chain driven garage door opener.
Grasp the chain 1 foot from where it connects to the end of the threaded chain anchor.
The most common cause of a chain being loose and appearing broken is a broken gear and sprocket.
It will usually run about 200 00 total.
Loosen the bolts on the chain pulley that s attached at the top of the arm and slide the pulley one inch toward the motor.
Pull the chain off the motor unit sprocket and out of the chain spreader.
Garage door openers.
Immediate troubleshooting is required and a new garage door chain will need to be installed in place of the old one.
This can be easily replaced by a garage door service technician.
Press down on the chain with your finger.
If the chain on your garage door is rusty you need to apply lubricant into it to loosen the corrosion.
Slide the outer trolley away from the inner trolley.
Periodic maintenance of a liftmaster chain driven garage door opener includes lubricating the chain and greasing the chain rail.
I hope this will help.
A broken garage door chain will immediately impact your garage door s operation and render its automatic motorized capability effectively useless.
To do this put some lubricant on a piece of rag this use the rag to wipe the chain.