The main automatic transmission to use a torque converter (in lieu of a fluid coupling) was the Buick Dynaflow, which was launched with the 1948 model yr. In regular driving, the Dynaflow applied only the top rated gear, counting on the torque multiplication of your torque convertor at reduce speeds. https://devinhlmjg.fitnell.com/74929028/the-smart-trick-of-gearbox-auto-that-no-one-is-discussing