Examine the metal tracks on the door for dents or bumps.
Garage door chain drive fix.
Slide the pulley toward the garage door until the chain is stretched tight then move it toward the motor until the middle of the chain touches the upper side of the chain arm.
The chain wraps around this sprocket as well as the gear and sprocket at the motor.
Sprocket is at the end of the opener rail closest to the garage door opening.
Make sure the tracks are aligned properly.
Tighten the bolts on.
If there are some you can use a wood block and your hammer to fix the dents.
Press the remote or the wall mounted start switch listen to the motor and watch the movement of the chain.
If the motor hums but the chain doesn t move that indicates a problem with the motor.
This video from sears partsdirect shows how to replace the chain and cable assembly on a chain drive garage door opener.
Start by checking the things below to see if it is the problem lies with the garage door.