The initial automatic transmission to make use of a torque converter (rather than a fluid coupling) was the Buick Dynaflow, which was launched to the 1948 design year. In ordinary driving, the Dynaflow applied only the major equipment, relying on the torque multiplication with the torque convertor at reduced speeds. https://gearboxauto53961.fireblogz.com/65413405/rumored-buzz-on-gearbox-auto