Compared with the three-axle transmission, the two-axle transmission has the advantages of simple structure, compact structure, high transmission efficiency and low noise. The front wheel drive of front engine is usually used in cars, because it makes the power-transmission system compact, the maneuverability is good, and the quality of the car can be reduced by 6% ~ 10% . The two-shaft transmission facilitates this arrangement and simplifies the structure of the transmission system. As shown in the figure, the second shaft (the output shaft) of the two-shaft transmission is integrated with the drive gear of the main reducer. When the engine is in Longitudinal position, the main reducer can be a spiral bevel gear or a double-sided gear; when the engine is in transverse position, a cylindrical gear can be used, thus, the manufacturing process is simplified and the cost is reduced. In addition to the reverse gear commonly used sliding gears, other gear are used constant mesh helical gear transmission, low-grade synchronizer installed in the second shaft, this is because the first gear size is small, the installation of synchronizer difficulties; The high-end synchronizer can also be mounted on the back end of the first shaft, as shown in figure.