The torque converter helps an automatic transmission connect and disconnect from the powertrain. It functions like a clutch in a manual transmission.
The torque converter is a fluid coupling that contains three elements, including the impeller, turbine and stator. Unlike a traditional fluid coupling, a torque converter is able to multiply turning power.
The impeller and turbine are fan-like parts that move in transmission fluid. The impeller connects to the engine and the turbine connects to transmission input shaft. Unless the vehicle is in neutral or park, the motion of the turbine makes the vehicle move. The stator sits between the impeller and turbine and aids fluid flow. The impeller spins and pushes fluid against the turbine and causes it to spin. The faster the impeller, the faster the turbine,which means the vehicle will move faster.