Liftmaster K77-39430, COVER, RSW12UL
The LiftMaster K77-39430 is a replacement cover for select RSW12UL residential swing gate operators. It is commonly used when the original cover has been broken by impact, faded or warped from sun exposure, damaged during service, or lost after a repair. The RSW12UL is an outdoor DC swing gate operator, so the cabinet cover plays an important role in protecting the battery backup area, control board, wiring, and internal components from the environment. A damaged cover may allow water and pests into the operator, which can create corrosion, weak battery connections, blown accessories, or intermittent gate movement. Because similar LiftMaster covers may fit different cabinet families, this part should be confirmed by model and illustrated parts diagram before ordering.
Compatible With
Compatible with select LiftMaster RSW12UL residential swing gate operators where K77-39430 is specified. Commonly associated with RSW12UL and RSW12ULMC newer UL-listed residential swing gate operator applications. Verify by operator data label, cabinet style, and parts diagram.
Features and Specifications
| Manufacturer | LiftMaster |
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| Product Type | Operator cover / housing cover |
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| Part Number | K77-39430 |
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| Application | Replacement cover for select RSW12UL swing gate operators |
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| Compatible Operator Type | RSW12UL / RSW12ULMC when specified by parts diagram |
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| Material / Finish | Gray outdoor operator cover |
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| Notes | Cover only; does not include electronics unless specifically listed |
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Also Known As / Related Part Numbers
K77-39430, 77-39430, LM-K77-39430. Related but different cover references include K77-37854, K77-37856, K77-39425, K77-39427, K77-39428, and other RSW12U/RSW12UL cover listings.
Technician Note
Use this part when the installed operator parts diagram calls for the exact LiftMaster part number. Similar covers, harnesses, bushings, and mounting plates may look close in photos but can differ by cabinet generation, model suffix, voltage/phase configuration, or mounting layout.
Before Ordering Checklist
- Confirm the operator model is RSW12UL or a confirmed RSW12ULMC application.
- Check the parts diagram for K77-39430 before ordering.
- Compare cover shape, lock location, access openings, and cabinet style.
- Do not assume RSL12UL, CSL24UL, or CSW24UL covers interchange.
- Inspect batteries, wiring, and board area if the old cover was missing.
Important Ordering Warnings
K77-39430 is specific to RSW12UL-style cover applications. Do not install on a different LiftMaster cabinet family unless the illustrated parts diagram confirms the part number.
Professional Advisory
Gate operator covers, harnesses, and mechanical service parts should be installed with the operator power shut off and the gate secured against movement. For high-voltage wiring, damaged conductors, exposed electrical components, or unsafe gate movement, use a qualified gate technician.
Product Questions and Answers
What operator does K77-39430 fit?
K77-39430 is commonly listed for LiftMaster RSW12UL residential swing gate operator cover applications, including RSW12ULMC-style references where supported.
Is this a complete operator housing?
It is a replacement cover component. The base cabinet, electronics, batteries, and mechanical parts are separate unless a current kit listing states otherwise.
Can a damaged cover cause operator problems?
Yes. A cracked or missing cover can allow water, insects, and debris into the operator, which may lead to wiring corrosion, battery trouble, or board damage.
Is K77-39430 the same as K77-39425?
No. They are related LiftMaster gray cover numbers, but K77-39430 is tied to RSW12UL cover applications. Use the parts diagram to choose correctly.
Should I replace the cover after storm or impact damage?
Yes, if the cover no longer seals or secures correctly. Also inspect the inside of the operator for water intrusion and damaged wiring.
