Marantec
Stripped Drive Gear or Broken Sprocket
Garage door opener hums but door does not move; chain or belt does not travel along the rail.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Worn nylon drive gear inside Marantec head, Broken output sprocket on top of opener, Excessive door load causing gear failure, Lack of lubrication in drive train
How to Fix / Troubleshooting
Safety first: Unplug the opener before disassembly. Support the door with the opener disconnected so it cannot fall.
- Verify symptom: Activate the opener briefly (before unplugging) and observe: if the motor hums but the chain/belt does not move, the internal gear/sprocket is suspect.
- Remove opener cover: With power disconnected, remove the screws holding the Marantec head cover and inspect the drive gear and sprocket area for plastic shavings or broken parts.
- Replace gear/sprocket kit: If the nylon gear teeth are worn smooth or the sprocket is broken, install a Marantec gear and sprocket repair kit specific to your model, following the kit instructions.
- Lubricate: Lightly grease the new gear and moving parts with manufacturer‑approved lubricant.
- Reassemble and test: Reinstall the cover, restore power, and run a full open/close cycle. Confirm smooth movement without slipping.
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Repair Difficulty
Hard
4/5
Required Part
Marantec Gear and Sprocket Kit
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