Torque Converter
The torque converter usually assumes the role of the clutch in automatic transmissions and transmits the drive forces between the engine and transmission. Torque converters are generally hydrodynamic, meaning they transmit the engine's drive torque by means of the flow forces acting in a fluid, usually oil. The torque converter is particularly effective when pulling away (engine running, car stationary) thanks to its ability to transmit changes in torque and engine speed perfectly smoothly.