Ford C4 Identificationby Floyd Drake III
The Ford C4 automatic transmission, manufactured between 1964 and 1981, is easily identified by sight, measurement and Ford part numbers. It is a two-speed automatic, used extensively in both passenger cars and trucks.
All C4s came with an identification tag, attached to the transmission on the passenger side. This tag contains all the necessary identification information and if not present, use the following visual techniques: the C4 measures between 17 and 18 inches long and has an almost-square pan with 11 bolts. The pan measures 10-by-9 inches.
The part number location varies on C4 transmissions and is used to determine year of manufacture. The number is normally four-digits long, consisting of both numbers and letters. C5SP, for example, decodes as a 1965 transmission. Ford begins with the decade designation, "A," for the 1940s, "B," for the 1950s, etc. The number represents the decade year.
The C4 is split into two main categories: pre-1970 and 1970 and later. Ford improved the transmission in 1970 and the best way to identify either is to count the input shaft splines. 1970 and later models have 26 splines instead of 24. These later models were also issued with 157- or 164-tooth bell housings. Both C4 editions have removable bell housings.
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