What turns the torque converter cover and impeller on an automatic transmission?

In an automatic transmission, the torque converter cover and impeller are turned by the engine's power. Specifically, the engine's flywheel connects to the torque converter, transferring rotational energy. As the engine runs, it turns the flywheel, which in turn rotates the torque converter cover and impeller, allowing for the transfer of power to the transmission and ultimately to the wheels. This process enables smooth acceleration and deceleration without the need for manual gear changes.