Liftmaster K75-40403, REDUCTION SPROCKET KIT
The LiftMaster K75-40403 is a reduction sprocket service kit for SL920 slide gate operators. It is used in the reduction drive area where sprocket sizing helps control output speed and torque for the gate system.
A worn reduction sprocket can cause chain noise, slipping, uneven travel, poor force transfer, or premature wear on related drive components. This kit should be selected by matching the original reduction sprocket, chain size, bore, and keyway to the SL920 parts diagram.
Compatible With
- LiftMaster SL920 slide gate operators
- Select SL920 service assemblies using the K75-40403 reduction sprocket
- Not a substitute for K75-40401 or K75-40402 drive sprocket kits
- Verify sprocket size, bore, chain type, and operator parts diagram
Also Known As / Related Part Numbers
- K75-40403
- 75-40403
- LM-K75-40403
- 35B54 sprocket reference where listed
- Reduction sprocket service kit
Features & Specifications
| Manufacturer | LiftMaster |
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| Product Type | Reduction sprocket kit |
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| Part Number | K75-40403 |
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| Application | Slide gate reduction drive sprocket service |
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| Compatible Operator Type | Commercial slide gate operator |
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| Common Model Reference | SL920 |
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| Known Component Reference | 35B54 sprocket with 1 inch bore references where listed |
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| Notes | Reduction sprocket position must match |
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Technician Note
Reduction sprocket wear should be checked along with chain condition, shaft condition, drive sprocket wear, and gate travel resistance. If a gate is heavy or dragging, sprocket wear may return quickly.
Before Ordering
- Confirm the operator is SL920 or lists K75-40403
- Verify it is the reduction sprocket position, not the drive sprocket
- Check bore, keyway, tooth count, and chain size
- Inspect related chain and sprockets
- Confirm gate rolls freely before replacing drive parts
Professional Advisory
Mechanical drive service on slide gates should be done with the operator powered down and the gate secured against movement.
Product Q&A
What operator is K75-40403 commonly used with?
K75-40403 is commonly listed for LiftMaster SL920 slide gate operator reduction sprocket service.
Is this a drive sprocket?
No. It is a reduction sprocket kit and should not be mixed up with K75-40401 or K75-40402 drive sprocket kits.
What are common symptoms of a worn reduction sprocket?
Noise, chain jumping, uneven travel, poor drive transfer, or visible sprocket tooth wear can point to sprocket problems.
Should the chain be inspected?
Yes. A stretched or rusty chain can damage a new sprocket.
Can this fit other slide gate operators?
Only if the parts diagram specifically lists K75-40403 or the exact matching sprocket configuration.
