The very first automatic transmission to utilize a torque converter (in place of a fluid coupling) was the Buick Dynaflow, which was released with the 1948 model yr. In typical driving, the Dynaflow used only the major gear, depending on the torque multiplication of your torque convertor at decreased speeds. https://daltonzhkml.win-blog.com/14708926/the-single-best-strategy-to-use-for-gearbox-auto