Virtually all modern automatic transmissions use a "lockup torque converter" for fuel efficiency. The lock-up clutch is activated once the transmission is fully

Virtually all modern automatic transmissions use a "lockup torque converter" for fuel efficiency. The lock-up clutch is activated once the transmission is fully coupled, and at that point the efficiency of the transmission is essentially identical to that of a manual transmission. http://en.wikipedia.org/wiki/Torque_converter#Lock-up_torque_converters http://en.wikipedia.org/wiki/Torque_converter#Lock-up_torque...