The first automatic transmission to implement a torque converter (as an alternative to a fluid coupling) was the Buick Dynaflow, which was introduced for that 1948 model yr. In typical driving, the Dynaflow used just the leading equipment, depending on the torque multiplication from the torque convertor at lower speeds. https://andysaehl.mdkblog.com/39993645/details-fiction-and-gearbox-auto