The main automatic transmission to utilize a torque converter (as opposed to a fluid coupling) was the Buick Dynaflow, which was launched for the 1948 design 12 months. In ordinary driving, the Dynaflow used only the top equipment, counting on the torque multiplication from the torque convertor at reduced speeds. https://gearboxauto13567.dailyblogzz.com/34213153/the-2-minute-rule-for-gearbox-auto