The 1st automatic transmission to use a torque converter (instead of a fluid coupling) was the Buick Dynaflow, which was launched with the 1948 model yr. In usual driving, the Dynaflow used only the top gear, depending on the torque multiplication of the torque convertor at decrease speeds. The Dynaflow https://gearbox-auto87417.estate-blog.com/33298534/a-review-of-gearbox-auto