The initial automatic transmission to implement a torque converter (instead of a fluid coupling) was the Buick Dynaflow, which was introduced for your 1948 model year. In normal driving, the Dynaflow made use of just the top equipment, depending on the torque multiplication with the torque convertor at decrease speeds. https://gearboxauto63950.blogdeazar.com/34312982/a-review-of-gearbox-auto