The initial automatic transmission to work with a torque converter (in lieu of a fluid coupling) was the Buick Dynaflow, which was launched to the 1948 design year. In regular driving, the Dynaflow utilized only the major equipment, depending on the torque multiplication on the torque convertor at reduce speeds. https://martinsbfij.blogrenanda.com/40460015/facts-about-gearbox-auto-revealed