The 1st automatic transmission to employ a torque converter (as an alternative to a fluid coupling) was the Buick Dynaflow, which was released to the 1948 product yr. In ordinary driving, the Dynaflow utilised only the major gear, counting on the torque multiplication with the torque convertor at lessen speeds. https://gearbox-auto10851.theobloggers.com/40407625/gearbox-auto-fundamentals-explained