The power transmission device between the automobile engine and the drive wheels is called the drive train of the automobile. It should ensure that the car has the necessary traction and speed in various driving conditions, as well as the function of ensuring the coordination between the traction force and the vehicle speed, so that the car has good power and fuel economy; it should also ensure that the car can reverse, and The left and right drive wheels can accommodate differential speed requirements and enable power transfer to be smoothly combined or completely and quickly separated as needed. The drive train includes the clutch, transmission, drive shaft, final drive, differential and half shaft. The power transmission device between the automobile engine and the drive wheels is called the drive train of the automobile.