Consider the following issues comprehensively：

1. Whether the gear material meets the requirements
2. Whether the accuracy of gear machining meets the requirements, so it is necessary to conduct a comprehensive inspection of the gear parameters, tooth profile, tooth direction and root scanning
3. Whether the bearing is qualified
4. Hardness of root after heat treatment
5. Whether undercutting occurs

Possible conditions of gear wear：

1. Material problems
2. Heat treatment problems
3. Incorrect machining tooth shape
4. Partial load
5. Overload or insufficient strength
6. Poor lubrication

The main causes of gear damage can be roughly divided into: wear; pitting, peeling, carburizing layer fragmentation; fatigue; impact; corrugation, arris and cold deformation. Most gear damage is due to excessive gear load, or shock or shock loads caused by incorrect shifting or clutch operation. If there is a defect in a gear, it can only be determined by metallographic examination.