Liftmaster 041A1340, CHAIN EXTENSION KIT, #48, 3"
The LiftMaster 041A1340 chain extension kit is a small but important service part for chain drive garage door opener rail assemblies. It provides a #48 chain extension section and master link hardware used when the chain length needs to be corrected during opener repair, rail service, or reassembly. On a chain drive opener, the chain length and master link position affect trolley travel, tension adjustment, and how smoothly the opener pulls the door through the open and close cycle.
This is not a universal repair for every noisy or loose chain. If the chain is sagging because the sprocket, trolley, pulley bracket, or tension hardware is worn, those parts should be inspected before adding an extension section. The correct chain pitch and rail style must match the existing opener. For best results, compare the installed chain, the opener model number, and the parts diagram before ordering.
Common Replacement Reasons
- Original chain section or master link is missing during rail reassembly
- Chain length needs a factory-style 3 inch #48 extension
- Existing master link hardware is damaged or corroded
- Service work was performed on a compatible chain drive rail
- Chain repair is needed without replacing the full rail assembly
Compatible With
Common Compatible Applications
- Most LiftMaster chain drive garage door openers that call for a #48 3 inch chain extension
- Most Chamberlain chain drive garage door openers that call for 041A1340 or 41A5648
- Select Craftsman/Sears openers built by Chamberlain Group when the parts diagram calls for the same chain extension
Important Compatibility Notes
- Use only on chain drive rail systems, not belt drive or screw drive openers
- Verify #48 chain size and rail length before ordering
- Not a fix for a worn drive gear, stripped sprocket, damaged trolley, or incorrect rail
Also Known As / Related Part Numbers
- 041A1340
- 41A1340
- 41A5648
- 041A5648
- 4A1340
- #48 chain extension kit
- 3 inch chain extension
- master link kit
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Chain extension kit |
| Part Number | 041A1340 |
| Application | Garage door opener chain drive rail service |
| Compatible Operator Type | Select LiftMaster, Chamberlain, and related chain drive garage door openers |
| Chain Size | #48 |
| Extension Length | 3 inch chain section |
| Included Components | Chain extension and 2 master link kits |
| Notes | Verify opener model, chain size, and rail diagram before ordering |
Technician Note
A short chain extension should only be used where the factory parts diagram calls for it. Do not use it to mask an overstretched chain or a worn sprocket because that can create travel problems and extra strain on the opener.
Before Ordering
- Confirm the opener is a chain drive model
- Match the part number 041A1340 or related number on the parts diagram
- Confirm the existing chain is #48 size
- Inspect the sprocket, trolley, pulley bracket, and chain tensioner
- Do not use this part on belt drive or screw drive openers
Professional Advisory
Disconnect power before opening an operator cover or working around the drive system. For damaged wiring, abnormal door movement, missing safety devices, or electrical diagnosis, use a qualified garage door technician.
Product Questions and Answers
What does the 041A1340 kit include?
It includes a #48 chain extension section and two master link kits for compatible chain drive garage door opener rail assemblies.
Is this a complete chain replacement?
No. It is a short extension kit, not a full chain, rail, trolley, or complete drive system replacement.
Can this be used on a belt drive opener?
No. The 041A1340 kit is for select chain drive opener applications only.
Why would a chain extension be needed?
It may be needed during rail service, chain reassembly, or when the parts diagram calls for a short factory-style chain extension section.
Should I replace other parts at the same time?
Inspect the sprocket, pulley bracket, trolley, and chain tension hardware. A loose or noisy chain can be caused by worn drive parts, not just chain length.
