The first automatic transmission to make use of a torque converter (rather than a fluid coupling) was the Buick Dynaflow, which was introduced for the 1948 model calendar year. In ordinary driving, the Dynaflow made use of just the best gear, depending on the torque multiplication on the torque convertor https://gearbox-auto20628.ampblogs.com/5-tips-about-gearbox-auto-you-can-use-today-70831040