The initial automatic transmission to work with a torque converter (in place of a fluid coupling) was the Buick Dynaflow, which was introduced for the 1948 design year. In ordinary driving, the Dynaflow applied only the best gear, counting on the torque multiplication from the torque convertor at reduce speeds. https://gearboxauto75306.anchor-blog.com/14099193/what-does-gearbox-auto-mean