The first automatic transmission to employ a torque converter (in place of a fluid coupling) was the Buick Dynaflow, which was introduced with the 1948 product yr. In normal driving, the Dynaflow applied only the top rated gear, depending on the torque multiplication in the torque convertor at lessen speeds. https://gearbox-auto31852.anchor-blog.com/13964383/gearbox-auto-things-to-know-before-you-buy