The primary automatic transmission to employ a torque converter (in place of a fluid coupling) was the Buick Dynaflow, which was released for your 1948 model calendar year. In standard driving, the Dynaflow applied only the best gear, relying on the torque multiplication in the torque convertor at reduced speeds. https://deanrwvsp.blogitright.com/34274659/the-best-side-of-gearbox-auto