Ford C4 transmission

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ManufacturerFord Motor Company
Class3-speed longitudinal automatic transmission
ManualsService Manual

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. A few C4s were built with a big-block bellhousing to use with Ford 335 engines, notably the 351M, but these are very 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.

Year & Model breakdown:

  • 1964–1966 Dual-Range, 24/24 spline, castings: C4, C5, C6
  • 1967–1969 Select Shift, 24/24 spline, castings: C7, C8, C9
  • 1970–1970 Select Shift, 26/26 spline, castings: D0
  • 1971–1979 Select Shift, 26/24 spline, castings: D1, D2, D3, D4, D5, D6, D7, D8, D9



The C4 was replaced in 1982 by the C5, which was essentially a improved C4 with a lock-up clutch in the torque converter to improve highway fuel economy. It bore the casting numbers D2, D3, D4, D5, and D6, 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 front wheel drive AXOD.


See also