One of my garage doors has suddenly started making an unusual noise when raising the door. It still works fine, but I'm guessing from this sound that won't be for long. It's an Overhead Door opener and it's only about 5 years old. It's belt driven and the tension on the belt is the same as on my other door. I've visually inspected the door itself, the rails, the belt, and the belt guide, and everything appears normal. I lubed the door itself and the rollers about 2 years ago. It's hard to be sure where the noise is coming from. I think it's the motor housing, but the sounds gets transmitted through the door so it's hard to be sure.

My question is, has anyone heard a noise like this before and can suggest where I should look before I spend money on a technician? I've included a brief video so you can hear the sound. The sound I'm asking about is the rhythmic thunking or banging. The video is just for the sound and contains nothing of visual interest.

UPDATE: I followed the advice @Jasen offered in his answer and disconnected the door from the motor. The sound is coming from within the motor housing, not the door.

  • You need to unhook the automatic opener and operate the door manually. At that point it should be easier to use tactile feedback to find the problem. NEVER run a power opener on a suspect or broken door as it will ram the door through the damage and make things worse. A properly installed door can operate with one hand. I'm talking the big 12' wide 16' tall semitruck size doors. Dec 27, 2022 at 4:38
  • @Harper-ReinstateMonica Thank you. That's pretty much what the top-voted answer says. Dec 27, 2022 at 4:48

2 Answers 2


First you need to figure out where the noise is coming from. perhaps pull the emergency string and disconnect the door from the opener - then you'll be able to test each part separately.

Rythmic noises usually come from something that rotates at the same rate as the noise, if it's coming from the motor unit check the drive sprocket, and tension sprocket etc. if it's coming from the door, check the wheels.

  • 1
    Disconnecting the door from the opener is a brilliant idea. Thank you. +1 Dec 26, 2022 at 22:16
  • Did as you suggested and the sound is coming from within the motor housing. Dec 28, 2022 at 5:31
  • sounds like there's something broken inside there. possibly the gear on the other end of the output shaft.
    – Jasen
    Dec 28, 2022 at 6:53

The temperatures here finally warmed to the point where I could bear to work in an unheated garage, and I found the problem. It exactly matches the symptoms of the rhythmic banging and what @Jasen predicted in his answer.

A tooth broke off the gear on the output shaft of the motor. Unfortunately, the gear is plastic and isn't replaceable. The entire motor will have to be replaced at a cost of about $350 if I do it myself or $500 if I pay to have it done.

Nice example of planned obsolescence. There's no other explanation for making a gear out of plastic that's pulling a substantial load and then making it unreplaceable.

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