Differences Between Cruise-O-Matic and C-4 Automatic Transmission

The Cruise-O-Matic derived from the original Ford-O-Matic automatic transmission that debuted in 1951. The Ford-O-Matic was Ford’s first automatic transmission for mass-produced cars and trucks. There also was a Merc-O-Matic for Ford’s Mercury line of cars. The names were simply marketing terms at a time when automatic transmissions were new technology and a novelty for buyers. These transmissions featured a two-piece cast-iron case and a cast-iron or aluminum bell housing. The Ford-O-Matics transferred engine power for Cadillacs during a brief period in 1953 when General Motors’ transmission factory caught fire. Some Dodge and International-Harvester vehicles, as well as Checker Cabs, were also equipped with the Ford-O-Matic.

The Ford-O-Matic was a cumbersome, frustrating piece of technology. It started in second gear when placed in “Drive” and then shifted to third. Drivers had to manually shift into low at the “L” position and use it as a first gear. Drivers had a tendency to forget to manually shift out of low to Drive, often putting a strain on the transmission and shortening its life. The Cruise-O-Matic arrived in 1958 and solved that problem. The Cruise-O-Matic featured a sprag, which offered another “D” or Drive position and marked with a green dot. The new automatic still featured a Low position, but the sprag allowed the transmission to shift automatically from low to second to third. This green dot gear pattern remained until 1967, when Ford replaced it with the now-common 1-2-D pattern for three-speeds.

The C-4 arrived in 1964 and like the Cruise-O-Matic was a hydraulically controlled rear-wheel-drive automatic. It was commonly matched with six-cylinder and small-block V-8 engines.The C-4 differed from the Cruise-O-Matic with its three-piece case consisting of the main case, bell housing and tail housing. Although it used a Simpson planetary gear set like the Cruise-O-Matic, the C-4 was considerably lighter. While the Cruise-O-Matic featured a three-bolt bell housing pattern, the C-4 had a five-bolt bell housing pattern in 1964 and six-bolt pattern starting in 1965. The C-4’s bolt patterns allowed the transmission to be easily adapted to many different engines. The C-4 also featured two dipstick variations: The dipstick in the case for passenger cars and the dipstick fitted directly in the transmission pan for trucks.

The gear ratios for the Cruise-O-Matic and C4 transmissions varied slightly. The Cruise-O-Matic had a 2.40-to-1 first gear ratio, 1.47-to-1 second gear and a 1.00-to-1 direct gear third. The reverse gear was 2.00-to-1. The C-4 had a 2.46-to-1 first gear, 1.46-to-1 second and 1.00-to-1 direct gear third. Its reverse was 2.18-to-1.