Impeller, Torque Converter

The impeller, also known as the pump, is the part of a torque converter that uses engine power to move transmission fluid and drive the turbine inside the converter. It’s attached to the converter's front cover, so it turns whenever the engine turns.

Think of two fans facing each other: one powered fan moves air that turns the other. A torque converter uses fluid inside a closed housing, with a stator that redirects returning fluid to help multiply torque under certain operating conditions.

The impeller’s design helps determine how the converter transfers power. Its blade angle, and internal flow passages affect stall speed, torque capacity, and efficiency.

Despite being called the 'pump,' the impeller is separate from the transmission’s oil pump, which supplies pressure for clutch operation and lubrication.