LiftMaster K75-12858 Torque Limiter Assembly Kit
The LiftMaster K75-12858 Torque Limiter Assembly Kit is a genuine-style replacement clutch and torque limiter kit used in select LiftMaster commercial operator drive systems. The torque limiter is part of the mechanical drive protection system. It helps reduce damage to the operator when excessive resistance or load is applied to the drive train.
This kit is most often used when the operator clutch is slipping, seized, damaged, out of adjustment, or when the existing torque limiter hardware is worn beyond normal service. It is a service part for commercial installations where proper mechanical adjustment and operator safety checks are important after replacement.
What This Part Does
This replacement part is used to restore the correct mechanical or electrical function in the compatible LiftMaster commercial operator assembly. It should be selected by the manufacturer part number, the operator model, and the replacement parts diagram. Many LiftMaster commercial components look similar but are not interchangeable across operator families, voltage configurations, shaft sizes, rail assemblies, or production generations.
Compatible With
The following compatibility list is written from available LiftMaster-style parts references, distributor listings, and commercial operator parts breakdowns. Use it as a strong application guide, but match the exact operator tag and parts diagram before installation.
- Select LiftMaster GT commercial trolley operators
- Select LiftMaster T commercial trolley operators when parts diagram confirms K75-12858
- LiftMaster SL580 commercial slide gate operators
- LiftMaster SL590 commercial slide gate operators
- LiftMaster SL595 commercial slide gate operators
- Select LiftMaster GSL commercial slide gate operator systems
- Select LiftMaster XGSL commercial slide gate operator systems
- Select LiftMaster GSD commercial slide gate operator systems
- Other LiftMaster commercial operator drive systems that specify K75-12858 in the replacement parts diagram
Also Known As / Related Part Numbers
These are manufacturer numbers, older number formats, catalog aliases, component references, or closely related parts customers may use when searching. Related numbers are not always interchangeable unless the operator parts diagram confirms the match.
- K75-12858
- 75-12858
- K75-12858 torque limiter kit
- K75-12858 clutch assembly
- Torque limiter assembly kit
- Torque limiter sprocket assembly
- 40A25 torque limiter sprocket, component reference
- Clutch disc, component reference
- Pressure plate, component reference
- Belleville washer / bell washer, component reference
- 1-1/2 inch hex jam nut, component reference
- 1/4 x 1-1/2 key, component reference
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Torque Limiter Assembly Kit |
| Part Number | K75-12858 |
| Application | Commercial operator clutch and torque limiter replacement |
| Compatible Operator Type | Select LiftMaster commercial door operators and commercial slide gate operators |
| Common Operator Families | GT, T, SL580, SL590, SL595, GSL, XGSL, and GSD when confirmed by parts diagram |
| Kit Function | Provides torque limiting and clutch protection in the operator drive system |
| Notes | Confirm operator model, shaft size, and replacement parts diagram before service. |
Technician Note
Commercial LiftMaster replacement parts should be matched to the operator model, serial range, voltage, handing, shaft size, rail style, and parts diagram. Do not order by appearance alone. Similar frames, pulleys, shafts, electrical boxes, bearings, and trolley parts may have different dimensions or mounting geometry even when the product names sound similar.
Before Ordering, Confirm
- Original part number or stamped/printed number on the existing component
- Exact LiftMaster operator model and series
- Voltage and phase when the product is electrical or part of an electrical box
- Right-hand / left-hand orientation when ordering frame parts
- Rail, trolley, shaft, chain, sprocket, or brake assembly style when ordering mechanical parts
- Parts diagram calls for this exact part number or a confirmed related number
- Door or gate moves freely and the operator is not being overloaded by a mechanical problem
Professional Advisory
Many of these parts are installed inside commercial door operators where moving components, stored spring force, and high-voltage wiring may be present. Disconnect power before service, follow the operator service manual, and use a qualified commercial door technician for internal drivetrain, brake, frame, or electrical box repairs. After replacement, test limits, controls, safety devices, brake action, and door balance before returning the operator to normal use.
Important Ordering Warnings
- Do not assume parts are interchangeable across T, GT, APT, MJ, MH, HMJ, GH, SD, GSD, LGO, or slide gate operator families.
- Electrical boxes and control parts must match voltage, phase, wiring type, and operator model.
- Handed frame parts must match left-hand or right-hand orientation.
- Mechanical drive parts should be checked with nearby shafts, bearings, sprockets, keys, chain, and brake hardware.
- If the operator failed because the door is binding, out of balance, or damaged, replacing the part alone may not solve the problem.
Questions & Answers
What does the K75-12858 torque limiter assembly do?
The K75-12858 assembly provides clutch and torque-limiting function in select LiftMaster commercial operator drive systems, helping protect the drivetrain from excessive load or obstruction forces.
Which operators commonly use the K75-12858 kit?
It is commonly associated with select LiftMaster GT, T, SL580, SL590, SL595, GSL, XGSL, and GSD operator applications when the replacement parts diagram calls for K75-12858.
Is this the same as a full motor replacement?
No. This is a torque limiter and clutch assembly kit, not a motor. It services the mechanical drive protection area of the operator.
What symptoms can point to a worn torque limiter?
Common signs include drive slipping, inconsistent movement, clutch noise, visible worn clutch hardware, or an operator that cannot transfer power correctly after the door or gate has been checked for binding.
What should be checked after installing this kit?
The clutch adjustment, operator travel, chain/sprocket alignment, door or gate movement, and safety devices should be checked by a qualified technician after installation.
