The first automatic transmission to make use of a torque converter (in place of a fluid coupling) was the Buick Dynaflow, which was launched to the 1948 design yr. In typical driving, the Dynaflow made use of just the prime gear, counting on the torque multiplication in the torque convertor https://jeffreyraegj.full-design.com/how-gearbox-auto-can-save-you-time-stress-and-money-76199790