| Manufacturer | Ford Motor Company |
|---|---|
| Production | 1964–1986 |
| Predecessor | Cruise-O-Matic |
| Successor | AOD |
| Class | 3-speed longitudinal automatic transmission |
| Related | Cruise-O-Matic |
The Ford C4 was a three-speed, medium-duty automatic transmission introduced in the 1964 model year and produced through 1986.
It featured an aluminum alloy three-piece case (bell housing, main case, and tailhousing). This was significantly lighter than earlier cast iron Cruise-O-Matic designs. It also used a Simpson planetary gearset.
It was used with Ford's inline six-cylinder engines and small V8 engines (see Ford Windsor engines), usually up to 302 in³ (5.0 L). By comparison, the 351 Windsor and 351 Cleveland small and intermediate-block engines were backed by the medium-duty FMX or the heavy-duty C6. Some C4s were built with a big-block bell housing to use with 351M V8s, but these are rare.
The early model C4 (1964-1969) used a .788-inch 24-spline input shaft, which was upgraded in 1970 to 26-spline and .839-inch. The upgrade also included a matching clutch hub of 26-spline. In 1971, Ford went to a 26/24-spline input shaft, meaning the torque-converter side is 26-spline and the clutch hub is 24-spline.
It is especially notable as the original automatic transmission option in the Ford Mustang.
The C4 was also found with valve bodies requiring a different number of bolts, 8-bolt vs 9-bolt. A 9-bolt valvebody can be used on either case, but a nut & bolt must be used on the valve body in the empty hole, dropping the bolt in from the top and using the nut on the bottom/filter side.
Modified C4s remain popular with hot rodders and drag racers due to their simplicity and durability.
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The C4 was replaced in 1982 by the C5, which was essentially an improved C4 with a lock-up clutch in the torque converter to improve highway fuel economy. It bore the casting numbers E2, E3, E4, E5, and E6, corresponding with the year it was produced. The C5 was phased out in 1986, replaced by the AOD. The production plant in Sharonville, Ohio was converted to production of the C6 transmission which was relocated from Livonia, Michigan, as the Livonia facility was converted to the AOD.
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