The 1st automatic transmission to work with a torque converter (as opposed to a fluid coupling) was the Buick Dynaflow, which was introduced for your 1948 design yr. In regular driving, the Dynaflow made use of only the top rated gear, counting on the torque multiplication of the torque convertor https://rafaelblqsv.ja-blog.com/34232259/gearbox-auto-an-overview