The very first automatic transmission to work with a torque converter (as an alternative to a fluid coupling) was the Buick Dynaflow, which was released with the 1948 design year. In normal driving, the Dynaflow employed only the prime gear, depending on the torque multiplication from the torque convertor at https://gearboxauto70245.bloggazza.com/32825140/the-ultimate-guide-to-gearbox-auto