★★★★★
Brass shavings everywhere when I opened the gear case — the old worm was completely chewed up. New one dropped right in. 30 minutes start to finish.
Liftmaster
41A2817 Worm and Drive Gear Replacement Kit
The worm-and-drive gear repair kit for Chamberlain, Liftmaster, and Sears Craftsman screw-drive openers built 1993 to present. When your screw-drive opener hums but doesn't lift the door, the brass worm gear has stripped — this kit replaces it.
$26.95
● In stock — ships next business day
🛟 Free technical support
📄 Installation & FAQ
- ModelLiftmaster 41A2817
- TypeWorm & drive gear kit
- FitsScrew-drive openers (1993–present)
- Compatible brandsLiftmaster · Chamberlain · Sears Craftsman
- Service greaseIncluded
- Repair time30–45 minutes (typical DIY)
In the box
- Brass worm gear
- Steel drive gear
- Mounting hardware
- Service grease
- Step-by-step instructions
Fits these openers
If your model isn't listed, send us a photo and we'll verify before you buy.
Liftmaster screw-drive
1345
1345R
1355
2500
2575
2585
2595
3500
3575
3585
3595
Chamberlain
HD800
HD900AA
Sears Craftsman
139.53985
139.53990
139.53991
139.53992
For chain-drive openers (visible bicycle-style chain along the rail), use the 41C4220A gear & sprocket kit instead.
When to replace your worm gear
Symptoms that point to a stripped worm:
- Motor hums or runs but the screw rod doesn't turn.
- Burning smell from the motor housing during operation.
- Door creeps open one inch at a time, then stops.