Liftmaster 81B170-1 Shaft Limit Worm
The LiftMaster 81B170-1 shaft limit worm, also referenced as K081B0170-1, is a replacement limit worm gear used inside select screw drive garage door opener limit assemblies. This part helps transfer movement within the opener's limit system so the unit can recognize door travel position more consistently.
Compatibility and Application
Used with select LiftMaster and Chamberlain screw drive garage door openers that list K081B0170-1, 081B0170-1, or 81B170-1 in the replacement parts diagram. It is not intended for chain drive, belt drive, wall mount, or commercial gate operator applications unless the parts breakdown specifically calls for this item.
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster / Chamberlain |
| Product Type | Shaft limit worm / limit worm gear |
| Part Number | K081B0170-1 |
| Application | Limit mechanism repair on select screw drive garage door openers |
| Compatible Operator Type | Select screw drive garage door openers |
| Notes | Small internal gear component; match by parts diagram before ordering |
Also Known As / Related Part Numbers
- K081B0170-1
- 081B0170-1
- 81B170-1
- Limit worm gear
- Shaft limit worm
Technician Note
A worn limit worm can cause travel settings to act inconsistent, especially on older screw drive operators. If the opener is also noisy, binding, or overrunning limits, look for rail wear or related limit assembly damage before assuming this part is the only issue.
Before Ordering
- Match K081B0170-1, 081B0170-1, or 81B170-1 to the opener parts diagram.
- Confirm the opener is a compatible screw drive model.
- Compare the removed worm gear shape and tooth condition to the replacement part.
- Inspect the nearby limit mechanism for broken clips, stripped gears, or missing hardware.
- Do not use this part as a substitute for unrelated belt or chain drive limit components.
Professional Advisory
Disconnect power before opening the opener cover. If the operator has damaged wiring, inconsistent door movement, or unsafe travel behavior after repair, have the opener inspected by a qualified garage door technician.
Product Questions & Answers
What does the LiftMaster 81B170-1 shaft limit worm do?
It works in the screw drive opener limit mechanism to help the unit track door travel and stop at the programmed open and close positions.
Is K081B0170-1 used on belt drive or chain drive openers?
No, this part is commonly associated with select screw drive garage door openers, not standard belt drive or chain drive rail assemblies.
What symptoms can point to a worn limit worm?
Possible symptoms include limits drifting, the door not stopping where expected, or visible wear on the original worm gear inside the limit assembly.
Does this part replace the complete limit assembly?
No, this listing is for the shaft limit worm gear component. Other limit parts may be needed if the assembly is cracked, stripped, or missing hardware.
Why should I compare the old part before ordering?
Several small screw drive limit parts look similar. Matching the removed part and the opener parts diagram helps avoid ordering a gear that does not engage correctly.
