This video from sears partsdirect shows how to replace the drive and worm gears on a chain drive garage door opener.
How to replace drive gear on sears garage door opener.
This is a video on how to change the gear sprockets in a craftsman garage door opener.
If yours is a belt drive you need a kit like this https amzn to 2zqns.
This was a craftsman model 139 53976srt.
The worm gear which attaches to the motor shaft meshes with the drive gear to spin the sprocket and drive the chain to open and close the garage door.
This diy repair guide explains how to replace the gear and sprocket assembly on a chain drive garage door opener.
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This diy repair guide explains how to replace the drive and worm gears on a chain drive garage door opener.
I replaced just the main gear with the sprocket and shaft assembly for 25 or so from a supplie.
Located at the top of the motor unit the gear and sprocket assembly drives the chain that opens and closes the garage door.
Kipa pack 3 drive gear for sears crafsman liftmaster chamberlain garage door openers 1984 up 41a2817 41c4220a 81b0045 drive gear 32 teeth bore size 1 2 durable top quality 4 6 out of 5 stars 40 9 75.
The worm gear attaches to the motor shaf.
If the gear and sprocket assembly breaks the motor runs but the door won t move.