The very first automatic transmission to employ a torque converter (in place of a fluid coupling) was the Buick Dynaflow, which was introduced for the 1948 design year. In regular driving, the Dynaflow used just the major gear, depending on the torque multiplication of the torque convertor at reduced speeds. https://gearbox-auto52075.myparisblog.com/34343889/examine-this-report-on-gearbox-auto