There are many brands and models of automatic transmissions, and the external shape and internal structure are also different, but their composition is basically the same, and they are all combined with a hydraulic torque converter and a gear-type automatic transmission. Common components include hydraulic torque converter, planetary gear mechanism, clutch, brake, oil pump, filter, pipeline, control valve body, speed regulator, etc. According to the functions of these components, they can be divided into hydraulic transformers. Torque device, transmission gear mechanism, fuel supply system, automatic shift control system and shift control mechanism are five parts.

The automatic transmission is composed of five parts: a hydraulic torque converter, a transmission gear mechanism, an oil supply system, an automatic shift control system and a shift control mechanism.

1. Automatic gearbox is a kind of transmission device that can automatically shift and operate according to the speed of the car and the engine speed, which appears relative to the manual gearbox;

2. At present, there are four common types of automatic transmissions in automobiles, namely, hydraulic automatic transmission (AT), mechanical continuously variable automatic transmission (CVT), electronically controlled mechanical automatic transmission (AMT) and dual-clutch automatic transmission ；

3. The core of automatic transmission is to realize automatic shifting. The so-called automatic shift refers to the fact that the driver manipulates the accelerator pedal (accelerator pedal) according to the needs of the driving process during the driving of the car, and the automatic transmission can automatically shift to different gears according to the engine load and the operating conditions of the car.