Liftmaster K74-40346, IDLER SPROCKET KIT
The Liftmaster K74-40346, IDLER SPROCKET KIT is a LiftMaster replacement Idler sprocket service kit used to restore the correct mechanical or electrical housing, drive, or service assembly on the matching operator. This is the type of part that should be selected by the operator model number and the LiftMaster replacement parts diagram, not by appearance alone. Similar LiftMaster and Elite service parts can look close in photos while using different mounting points, wiring locations, sprocket sizes, switch layouts, or enclosure dimensions.
For a service technician or parts-counter check, the important question is whether the original operator calls for K74-40346 or one of the related numbers listed below. When the correct part is used, it helps protect the operator assembly, maintain proper chain or switch alignment, or restore the intended electrical function without forcing a substitute part into the system. If the original part is damaged from impact, corrosion, water intrusion, heat, worn bearings, chain misalignment, or electrical failure, inspect the surrounding parts before installing the replacement so the same failure does not repeat.
Compatible With
This part is commonly associated with the following LiftMaster applications when confirmed by model number, configuration, and the replacement parts diagram:
- LiftMaster SL920 slide gate operators
- SL930 parts diagrams where K75-40346/K74-40346 idler sprocket service kit is called out
- related heavy-duty DC slide gate applications only when the parts diagram confirms the same service kit.
Important Compatibility Notes
Do not interchange with K74-40151 or other idler sprockets without comparing sprocket tooth count, bore, bearing, hardware, and diagram callout.
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Idler sprocket kit |
| Part Number | K74-40346 |
| Application | SL920/SL930 style idler sprocket service |
| Compatible Operator Type | Commercial slide gate operator |
| Included Components | Sprocket, bearing, bolt, jam nuts, lockwasher, and set screws as commonly listed |
| Notes | Commonly cross-referenced with K75-40346; verify by parts diagram. |
Also Known As / Related Part Numbers
The following numbers and search variations may be associated with this item, but related numbers should not be treated as automatic replacements unless confirmed by the manufacturer parts diagram:
- K74-40346
- K75-40346
- 74-40346
- 75-40346
- LM-K74-40346
- LM-K75-40346
- LiftMaster K74-40346
- LiftMaster K75-40346
- single idler sprocket kit
- idler sprocket service kit
Technician Note
Before replacing this part, inspect the connected hardware, wiring, mounting points, chain path, limit system, enclosure seal, and operator structure as applicable. A failed service part is often the visible result of another issue such as gate drag, poor alignment, water entry, worn chain, loose hardware, or damaged wiring.
Before Ordering Checklist
- Confirm the exact LiftMaster model number from the operator label.
- Compare the original part number, shape, mounting points, and service diagram callout.
- Check whether the operator is an older, UL, UL325, solar, metal-box, plastic-box, AC, DC, or heavy-duty generation.
- Verify that related part numbers are true matches and not just similar catalog references.
- For electrical parts, disconnect power and batteries before service and use a qualified technician when needed.
Professional Advisory
Gate operators are safety-related systems. Do not bypass monitored safety devices, limit systems, protective covers, or electrical protection to make a part fit. If the operator has unsafe movement, damaged wiring, failed safety devices, or high-voltage concerns, have the system inspected by a qualified gate technician.
Product Questions & Answers
Which operator is K74-40346 commonly used on?
K74-40346 is commonly listed for LiftMaster SL920 slide gate operators and appears in SL930 parts references as K75-40346/K74-40346 idler sprocket service kit.
What is included in the kit?
Listings commonly reference a sprocket, bearing, mounting bolt, jam nuts, lockwasher, and set screws. Confirm kit contents from the current package before ordering.
Is K74-40346 also known as K75-40346?
Yes. K75-40346 is a common related or alternate service-kit reference for this idler sprocket kit.
What happens when the idler sprocket is worn?
A worn idler sprocket can cause noisy chain travel, poor chain tracking, excessive chain wear, and inconsistent slide gate movement.
What else should be inspected?
Inspect the drive chain, drive sprocket, gearbox output, chain tension, gate rollers, and track condition so a new idler sprocket is not damaged by another problem.
