The first automatic transmission to make use of a torque converter (rather than a fluid coupling) was the Buick Dynaflow, which was introduced with the 1948 product year. In normal driving, the Dynaflow used just the best gear, counting on the torque multiplication of the torque convertor at decrease speeds. https://gearbox-auto77529.idblogz.com/34636853/gearbox-auto-an-overview