It is a frustrating sound: you press the button, the opener motor hums or runs like normal, but the garage door does not move an inch. The good news is that when the motor clearly runs and the door stays still, the problem almost always comes down to a few specific causes. Here is how to figure out which one you are dealing with.
First, the Easy One: the Trolley Is Disengaged
Every opener has a red release cord that disconnects the door from the motor so you can move it by hand during a power outage. If someone pulled that cord, the motor will run and the carriage will slide, but it is no longer connected to the door, so nothing moves. Re-engaging it is usually simple: close the door fully, then pull the cord back toward the motor or press the remote so the trolley clicks back into the carriage on the next cycle. Our guide to using the manual release walks through it. If re-engaging fixes it, you are done.
A Stripped Drive Gear
If the motor spins and you hear a grinding or whirring sound but nothing moves, the most common cause on older openers is a stripped drive gear. These are small plastic gears inside the opener head that wear down over years of use, especially on chain-drive units. Once the teeth strip, the motor turns freely but can no longer drive the chain or belt. This needs a technician to replace the gear kit, or, if the opener is old, it may be the moment to consider a new unit. Our guide to how long an opener lasts helps you decide.
A Broken Chain, Belt, or Trolley
Sometimes the motor and gear are fine, but the chain or belt that pulls the door has snapped or come off its sprocket, or the trolley itself has broken. In that case the motor runs, but there is nothing intact to move the door. This is a repair for a technician, forcing it or running the motor repeatedly can cause more damage.
The Door Is Too Heavy: a Broken Spring
Here is the important one for your safety. If the motor runs and strains, maybe the door jerks slightly or lifts an inch and stops, the problem may not be the opener at all. It may be a broken spring. Your springs, not the motor, do the heavy lifting. When a spring breaks, the door becomes far too heavy for the opener to lift, so the motor runs but cannot raise it. Do not keep pressing the button, and do not try to force the door, a door with a broken spring can slam down. Spring work is dangerous and should always be left to a professional.
What You Can Safely Check
- Re-engage the trolley using the release cord, as above. This is the one fix most homeowners can do themselves.
- Test the balance by hand. With the opener disconnected (release cord pulled) and the door closed, lift the door manually. If it is extremely heavy or will not stay open halfway, you likely have a spring problem, stop and call a pro.
- Listen to the motor. A free-spinning whir usually means a stripped gear or broken chain or belt. A straining hum usually means the door is too heavy, often a spring.
When to Call a Pro
If re-engaging the trolley did not fix it, the rest, stripped gears, a broken chain or belt, a damaged trolley, or a broken spring, all need a technician and the right parts. Running the motor against a stuck door only risks burning it out. Our team handles opener repair and replacement and spring repair across metro Atlanta, with same-day service and a free on-site estimate. We will find out why the motor is running without moving your door, and get it working safely again.