Cut-a-Way Torque Converter

This is an example of a modern automatic transmission's torque converter. It's the component that allows the vehicle to come to a complete stop without depressing a clutch pedal. It essentially works because transmission fluid is moved by a turbine, which is being turned by the engine's crankshaft, against another turbine connected to the front of the transmission. As you increase the speed (rotation) of the engine, it moves fluid against the other turbine causing it to turn to provide rotational power to the transmission. It loses 6% of the energy produced by the engine and a clutch was added inside the converter (as early as 1978) which connects the turbines together gaining the lost 6% of the engine's power. The clutch lining tends to glaze or wear causing a "rumble strip" feel above 35 miles per hour on light to medium throttle.