The 1st automatic transmission to implement a torque converter (rather than a fluid coupling) was the Buick Dynaflow, which was introduced for the 1948 product 12 months. In usual driving, the Dynaflow utilised just the top rated gear, relying on the torque multiplication on the torque convertor at reduced speeds. https://gearbox-auto20742.targetblogs.com/34269725/the-5-second-trick-for-gearbox-auto