The initial automatic transmission to employ a torque converter (as an alternative to a fluid coupling) was the Buick Dynaflow, which was released for the 1948 product yr. In standard driving, the Dynaflow utilized only the best gear, depending on the torque multiplication of the torque convertor at reduce speeds. https://gearbox-auto76420.theideasblog.com/34140310/gearbox-auto-fundamentals-explained