The very first automatic transmission to implement a torque converter (rather than a fluid coupling) was the Buick Dynaflow, which was launched to the 1948 product year. In normal driving, the Dynaflow applied only the best gear, relying on the torque multiplication of the torque convertor at decrease speeds. The https://jasperuutsp.thekatyblog.com/32555190/facts-about-gearbox-auto-revealed