Garage door motor runs, but chain does not move

Old 02-04-18, 12:00 PM
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Garage door motor runs, but chain does not move


I have a Lift Master model 139.53675SRT2 garage door opener that previously I had an issue with it getting stuck on the stop bolt when opening, so I loosened the chain to release the tension, ran it down and then re-tightened, and then lowered the up travel and it seemed to work fine for about 2 months.

Just the other night, we tried to open the door and it got stuck about half way up. The door moves fine on the rails with the manual release engaged. However, when we press the opener, it sounds as though the motor runs, but the chain does not move at all. If I hit the button again, it sounds like the motor reverses and tries to run in the other direction, again with no chain movement. It then stops when I hit the button a 3rd time.

I removed the cover plate partially and this is what the gears looked like inside. Is it likely that I just need to order a replacement kit and install a new one of these (to me it looks pretty bad, but I wondered if these other symptoms are consistent)? I found a video online that seems a good resource, but I just wanted a second opinion if this seems like the issue.
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Old 02-04-18, 12:18 PM
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Yep. you need a new gear kit. Don't cheap out and and only buy the single gear...get the whole kit.
Old 02-04-18, 12:23 PM
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Yes, that gear is intended to wear, or in an extreme case strip before anything more expensive goes. It's as likely as not that you're fine, but as long as your attention is on it raise and lower the door by hand. You should be able to do so with minimal effort, and it should stay when you stop moving it, whether raised, lowered, or midway. If not, your springs may need adjustment.
Old 02-04-18, 04:31 PM
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The Liftmaster Gear Kit 41C4220A is pretty widely available.
Comes with instructions and is easy to install.

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