Many automatic transmissions have been used by the Ford Motor Company throughout the years, from early Ford and Cruise-O-Matic to automatic overdrive four-speed transmissions. The C-series is Ford’s primary automatic transmission and are evolutionary, with the C3, C4, and C6 models each having an improvement on the last. All are visually identifiable, with other methods reserved for in-depth identification, such as the year of production. The prime identification source is the pan located on the bottom of the transmission; its shape and bolt count is indicative of which model transmission is present.