The first automatic transmission to make use of a torque converter (rather than a fluid coupling) was the Buick Dynaflow, which was introduced for that 1948 design year. In standard driving, the Dynaflow employed just the best gear, depending on the torque multiplication from the torque convertor at lower speeds. https://gearboxauto87417.slypage.com/34725571/rumored-buzz-on-gearbox-auto