The 1st automatic transmission to utilize a torque converter (as an alternative to a fluid coupling) was the Buick Dynaflow, which was launched to the 1948 design year. In standard driving, the Dynaflow utilized just the prime gear, counting on the torque multiplication from the torque convertor at decrease speeds. https://gearboxauto53962.blognody.com/35991856/5-essential-elements-for-gearbox-auto