How Does An Automatic Transmission Work

How does an automatic transmission work and what is its purpose? Many people know that they have automatic transmission but they don't know what it does.

The Creation of Automatic Transmission

Early cars and trucks had manual transmissions with a few gears, much like the stick-shift vehicles of today. But eventually, car manufacturers decided that the car should be able to automatically switch from gear to gear. After World War II, thousands of cars with automatic transmissions were brought to the market. Driving was no longer a stressful experience. People could just get in their car and go.

How it Works

The most important component of the automatic transmission is the torque converter, which increases the engine's turning power. The input shaft, or transmission shaft, connects the torque converter to the motor. The torque converter and the engine are not directly connected; rather, the engine turns the transmission through hydraulic coupling.

The torque converter has a pump, a turbine and a stator. The pump connects the engine's crankshaft to the turbine. The turbine is located at the center of the torque converter and connects to the transmission's input shaft. The stator regulates fluid pressure (the power transfer) between the transmission and the engine.

To maintain good gas mileage, many automatic transmissions also have a lockup clutch, which locks the turbine to the pump as the car reaches higher speeds. In doing this, the torque converter is bypassed until the car slows down again.


Remember that the automatic transmission is one of the most complex parts of a car. Because of this, it is expensive and can also be very fragile and undependable. Problems with your transmission can be extremely dangerous, so always make sure it is well taken care of and frequently checked up on.

If you have problems with your car and you suspect that it's the transmission, go to your car dealer. The dealership will have any exact parts that you need, as well as mechanics that specialize in your specific model. 

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