Clutch master cylinder and slave cylinder are equivalent to two hydraulic cylinders. There is an oil inlet and outlet pipe on the master cylinder and only one pipe on the slave cylinder. When the clutch is depressed, the pressure of the master cylinder is transmitted to the slave cylinder. The slave cylinder works. Separate the shift fork to separate the clutch pressure plate and plate from the flywheel. At this time, the gear shift can be started. Release the clutch, the slave cylinder stops working, the clutch pressure plate and plate contact the flywheel, the power transmission continues, and the oil of the slave cylinder flows back into the oil pot. When it is difficult to shift gears and the separation is not complete, it is necessary to check the clutch master cylinder and slave cylinder for oil leakage, and solve the problems in time to reduce wear. Others shall be checked accordingly.