The main automatic transmission to work with a torque converter (in place of a fluid coupling) was the Buick Dynaflow, which was introduced for that 1948 design yr. In standard driving, the Dynaflow utilized just the best gear, relying on the torque multiplication in the torque convertor at decreased speeds. https://gearboxauto32952.tribunablog.com/the-5-second-trick-for-gearbox-auto-48492182