The 1st automatic transmission to implement a torque converter (in lieu of a fluid coupling) was the Buick Dynaflow, which was released with the 1948 product 12 months. In standard driving, the Dynaflow utilised only the major equipment, relying on the torque multiplication with the torque convertor at decrease speeds. https://angelonziqx.blogoscience.com/40050244/gearbox-auto-an-overview