What is a torque converter and how does it work?

If you know about how manual transmissions work, you are aware of the fact that engines are bracketed to transmissions with a clutch. Without this vital connection, a car wouldn’t be able to come to a full stop without shutting down the engine. Cars with an automatic transmission don’t have a clutch that disconnects the engine from the transmission. A torque converter is what is used instead.

How a Torque Converter Works

To comprehend how it works, first picture two fans facing one another. If you turn one fan on, it will rapidly blow air over the other fan’s blades and make them spin. If you hold the second fan still, the first fan will keep going. In simple terms, that is how a torque converter works also. The first fan, or the impeller, is connected to the engine. The second fan, or turbine, is connected to the transmission input shaft. Any motion going through the turbine will cause the vehicle to move, unless the transmission is in park or neutral. Instead of using air like the opposing fans, however, torque converters use transmission fluid.

A car’s engine must be linked to the back wheels so the car will move forward, and disconnected so the motor can keep running when the car is stopped. One way to make this happen is to use a device like a clutch that manually connects and breaks away from the transmission. Another way, or in automatic transmission vehicles, is to use a fluid coupling, also known as torque converters.

Inside a Torque Converter

There are three main parts of torque converters, the pump, the stator, and the turbine. The pump inside is a kind of centrifugal pump. It functions in a way similar to the way a washing machine works. It pushes fluid to the outside, just like a washing machine flings clothes out during its spin cycle. The fluid then comes into the turbine blades, which is paired with the transmission. The turbine is what makes the transmission spin, which in short is what causes the car to move. The turbine blades are curved, so that after the transmission fluid enters the turbine, it has to change direction before it comes out. The change of direction is what makes the turbine spin. The fluid later leaves the turbine at the center of it, going in the opposite direction of the pump and the engine. The stator, which is located in the middle of the converter, averts fluid coming back from the turbine prior to it hitting the pump again. If the fluid was allowed to touch the pump, it would slow the motor down, and this is the reason a stator is in place.

When to Replace Your Torque Converter

Torque converter replacement is something you should consider if your transmission has sustained heavy damage. When it is worn out, this can keep transmission fluid from having the correct amount of pressure, which can have a negative impact on other parts in the transmission. Signs that a torque converter replacement is needed include shuddering and slipping when you try to shift gears.