The main automatic transmission to use a torque converter (as opposed to a fluid coupling) was the Buick Dynaflow, which was released for the 1948 model yr. In normal driving, the Dynaflow utilized just the top rated gear, counting on the torque multiplication of your torque convertor at decreased speeds. https://gearboxauto39517.blogerus.com/56298092/the-basic-principles-of-gearbox-auto