Repair is still necessary, but there is no need to replace the gear set. In addition, the main reason for abnormal sound of gearbox is spur gear.

For gears with small load and low rotation speed, after being knocked out alone, they can be partially repaired by cogging. The method is to etch or mill the dovetail groove at the tooth root on the machine tool, press in the new tooth blank with the same groove type with a certain amount of interference, and shape it after welding.

It can also be repaired by surfacing according to the damage degree of the gear. Before welding, use gasoline or hot alkaline water to clean the grease, rust and corrosion on the gear surface to expose the metallic luster. The electrode used for welding should be the same as or similar to the gear material as far as possible. After surfacing repair and machining repair of tooth profile, the repaired gear must be tempered to eliminate internal stress.