The initial automatic transmission to implement a torque converter (in lieu of a fluid coupling) was the Buick Dynaflow, which was introduced for your 1948 design 12 months. In normal driving, the Dynaflow utilised only the leading gear, counting on the torque multiplication in the torque convertor at decrease speeds. https://gearbox-auto57891.answerblogs.com/34004969/top-gearbox-auto-secrets