The initial automatic transmission to make use of a torque converter (as an alternative to a fluid coupling) was the Buick Dynaflow, which was released to the 1948 model yr. In typical driving, the Dynaflow used only the prime gear, relying on the torque multiplication on the torque convertor at https://gearboxauto29517.myparisblog.com/34707343/gearbox-auto-secrets