Dismount a magnetic plug by oil outdrain and check the presence of metal particles.If the amount of metal particles is extraordinary, it could mean the extraordinary wear in gearbox.

• 拆掉出油口的磁堵查看是否有金属物质吸附在上面，如果磁堵上吸附大量金属物质，则说明齿轮箱内可能存在磨损。