The torque converter makes it possible for the motor to idle once the cars is stopped Though the transmission contains a gear engaged. Since the name indicates, the torque converter converts (amplifies) the input torque with the motor into a better output torque. This particular function in the torque converter https://emiliovutsp.blogthisbiz.com/40803114/the-smart-trick-of-torque-converter-clutch-that-no-one-is-discussing