Remove the 3 nuts that hold the motor to the frame and then remove the worm gear.
How to replace a garage door opener gear.
Put a thin layer of the grease included in the kit on the gear.
Shut the garage door if it s not already closed.
With the gears back in place tighten the chain as directed in your owner s manual.
Remove the fastener ring from the straight door arm connected to the outer trolley.
Set the new gear in place and secure with the metal pin.
Push the pin in with a nail set in order to remove the gear.
I only had one stripped gear while the rest of the parts looked ok.
Pull the emergency release rope to release the trolley from the garage door.
Only replace the parts that are used on your garage door opener.
This is a video on how to change the gear sprockets in a craftsman garage door opener.
Slide the outer trolley away from the inner trolley.
Position a work table near the area under your motor unit to hold the garage door opener during the repair.
Remove retaining screws from the cover.
Press this lever and you will be able to remove the belt from the gear and pulley.
Install the new worm gear making sure the roll pin is properly seated in the new gear.
Release the tension on the belt with the small lever near the gear.
Re install other components in reverse order.
If not your opener might simply be shot and you ll need a new one.
Use all necessary replacement parts and reassemble the garage door opener in the reverse order.
If you have any other broken gears or parts replace those as well.
Pull the chain off the motor unit sprocket and out of the chain spreader.
Remove the outer nut and lock washer from the trolley threaded shaft and pull the threaded shaft out of the trolley.
This was a craftsman model 139 53976srt.
Replace the cover on the garage door opener plug it back in and start enjoying your now functioning garage door opener.
Shine the flashlight directly at the gear set.