The primary automatic transmission to use a torque converter (rather than a fluid coupling) was the Buick Dynaflow, which was released for that 1948 design year. In normal driving, the Dynaflow used just the best gear, depending on the torque multiplication of your torque convertor at decreased speeds. The Dynaflow https://landenenpss.tinyblogging.com/the-fact-about-gearbox-auto-that-no-one-is-suggesting-77814658