Does your garage door opener make a grinding noise but doesn’t move at all? Chances are, your main drive gear has bit the bullet. This is the plastic gear that comes in direct contact with the worm drive gear on the motor. It’s one of the most common garage door opener repair problems there is – since for some reason this garage door part is made of plastic, it wears out faster than the surrounding parts, and will also become brittle over time.

Replacing an internal garage door part on a chain drive opener can be a complicated repair, but not impossible to do yourself. Several components will need to be removed to get at the gear. You’ll need to get a replacement gear set. It’s not actually as complicated as it is tedious, so we recommend helping yourself keep track of the replacement process in some way, like keeping each part you remove organized by step.

How to Access Your Garage Door’s Main Drive Gear

• Before you do anything, close your garage door, unplug your garage door opener, and disengage the trolley by pulling the string that hangs from it.
• Loosen the tension nut on the trolley so you can get some slack in the chain.
• Remove the cap on the chain’s pulley and mark where the chain is sitting somehow. This will make it way easier to put the chain back at the end of all this.
• Okay, now we go to the main housing unit: the garage door opener itself. Remove the retaining screws from the cover and take a look at the gear set. If the gears have screwed up teeth, you can just replace them to solve the problem. (If there’s nothing wrong with the gear set, your garage door opener might simply be shot. In that case, you’ll need to call your local garage door service company to install a new one. Write down the make, model and serial number of your opener, which you can find on the back of the opener.)

Replacing the Drive Gear on Your Garage Door Opener

• To replace the gear, move the retaining clip and the drive gear. You should also take the limit switch assembly off at this point. You can usually do this by squeezing both sides and lifting. Don’t worry about the wires; it’s okay to let the assembly hang there for a bit.
• Remove the RPM sensor.
• Disconnect the 3 wires from the garage door opener’s motor. They should be white, red and blue. Make sure you note which one goes where so you don’t end up with a problem later.
• There should be 4 screws that hold the motor to the garage door opener’s frame. Remove these, being careful not to let the motor fall. Slide it off and set it aside somewhere safe, along with those loose screws.
• Remove the 3 screws that hold the sprocket assembly to the garage door opener’s main chassis.
• Now, to get the drive gear off the sprocket assembly, you need to release the little tension pins, which you can do by tapping a screw or a punch into the pin’s head.

Putting Your Garage Door Opener Back Together

• Alright. Now you basically just work your way backward until you get to the part about the chain.
• Plug the garage door opener back in and run it until that sprocket assembly does at least 1 cycle. Note that the trolley needs to be facing down for these next steps to go smoothly.
• Reinstall and tighten the chain. This is where marking and taping the chain will come in handy – it takes the guesswork of adjusting out of the equation.
• Now run your garage door opener, making sure it opens and closes to the correct positions. If it’s off at all, you can use the adjustment screws on the chassis itself to make small adjustments.

See? It’s more tedious than it is difficult. But if you’ve gone through all this and something’s still wrong, you may have gotten your garage door off track or off balance. Whenever you have complications with a garage door repair DIY, don’t dig yourself a deeper hole – call the pros instead. It’s going to save you time and frustration, and it guarantees the quality of the repair.

100% Guaranteed Local Garage Door Installation and Repair Services

If you’re in the areas of Sacramento or Seattle-Tacoma, call Sac’s Garage Door Repair any time of the day or night. We’ll be happy to help. We offer competitive rates in garage door installation and repair to Seattle, LA and Sacramento. Our services are 100% guaranteed. Our technicians are courteous and professional, not to mention fully insured. We’ll let you know if your garage door opener needs outright replacement or if we can simply repair the gears and replace some of the garage door’s parts for a cheaper alternative.