DIAGNOSIS This is typically a force setting issue, not a broken gear. The opener is applying too much downward force, causing the gear train to strain and grind as it pushes the door against the floor seal or slight misalignment.
FIX Adjust the down force limit setting.
- Locate the two force adjustment screws on the side of the motor unit. One is for UP force, one for DOWN.
- Find the DOWN force screw (consult 's diagram—do not guess). Turn it counter-clockwise by 1/8 of a turn.
- Test the door. If the grinding is reduced but the door reverses before hitting the floor, turn the screw clockwise slightly until it closes fully without grinding.
IF THAT DIDN'T WORK The noise might be from a dry chain or rail. Apply a light lubricant specifically for garage doors (white lithium grease or a silicone-based spray) to the chain, rollers, and hinge points on the door itself. Do not lubricate the plastic rail.
HEADS UP Never turn the force screws more than a full turn from their original position. If the grinding persists after small adjustments, you likely have a binding door track or a failing gear, which requires a professional.