Abandoned History: Ford's Cruise-O-Matic and the C Family of Automatic Transmissions (Part IV)
Last time on our Abandoned History coverage of Ford’s historical Cruise-O-Matic automatic transmission, we spent some time in Russia. Communist automaker GAZ liked Ford’s automatic and decided to lightly rework it into their “own” transmission rather than pay Ford to build it under license. The GAZ two- and three-speed automatics remained in use in the company’s passenger cars well into the Eighties, which was a very long time for a late Fifties transmission to live.
Shortly after GAZ made its copies, the real versions of the FX/MX Cruise-O-Matic and Ford-O-Matic were nearing the end of their respective service lives. The two-speed was naturally the first to go.
By the turn of the Sixties, the writing was already on the wall for the two-speed automatic. Three-speeds were the way of the future! The first of the Big Three to drop the two-speed was Chrysler, which discontinued its Powerflite in 1961. That final year it was only available on lower-level Dodge and Plymouth models.
And while Ford followed suit shortly thereafter, General Motors was not quite as ready to give up a two-speed. Their Powerglide lasted through 1973 and was offered in the Chevy Nova and Vega. At the end, Powerglide was only available to cheapskates who selected the Turbo-Thrift 250 inline-six. Back to Ford.
The simple as you please Ford-O-Matic continued as an offering in lower-end Ford and Mercury models through the 1963 model year. Recall from our previous entry that Ford marketed the transmission as a three-speed (though it used first gear in a few situations in Drive) until the Cruise-O-Matic came along. That transmission was a true three-speed, so the Ford-O-Matic became a two-speed to aid in marketing differentiation.
Ford needed a more modern automatic that was cheaper to make, lighter, and could be used in more applications than the old two-speed. In the early Sixties said replacement transmission was already in development, and would eventually be called the C4.
The old Ford-O-Matic was a very heavy transmission as it was made of cast iron. Ford used a slightly lighter material when it designed the F-O-M’s replacement: Aluminum alloy! The C4 had a three-piece case design that consisted of the main case, and an attached bell housing and tail housing. In addition to lighter materials, it used a simpler Simpson planetary gearset design. Recall the original Ford-O-Matic and its derivatives used a Ravigneaux planetary gearset.
Created by American engineer Howard Simpson (1892-1963), the Simpson gearset uses two planetary gears with a common sun gear. With its design, a Simpson gearset allows for three or four forward speeds, neutral, and one reverse speed. The design remained in use through the 2000s, when it was replaced by more complex transmission designs with a greater number of speeds. The main advantage of the Simpson design was its simplicity, which meant it was light. Keeping the weight down was the primary focus of the development of the C4.
The C4 used a different shift pattern than the Ford-O-Matic, and indeed other automatic passenger cars in general. At debut its shift pattern was Park, Reverse, Neutral, Drive 2, Drive 1, and Low. Drive 2 and Drive 1 were abbreviated as D2 and D1 on shift indicators.
D1 meant the transmission started in first gear, and then proceed to second and third as normal. Usage of D2 meant the transmission started in second gear, and first was not used in any circumstance. D2 and D1 were not familiar drive modes to consumers, and Ford later conceded and changed the layout to the much more familiar P, R, N, D, 2, L. When cars with the C4 were marketed, Ford called out the “SelectShift” feature of the two different Drive modes.
The C4 was used in medium-duty vehicles, usually with an inline-six engine or V8 of 302 cubic inches (5.0 liters) displacement or less. When it debuted in 1964 the C4 was immediately put to use in Lincolns, where it would remain through 1981. Other early usage included the Mustang, Ranchero, the Mercury Comet, and Ford’s Econoline vans.
Later in the decade and into the Seventies, it spread to the Mercury Montego and the Capri, as well as the Ford Torino, Thunderbird, Maverick, and Bronco. Aside from its continued Lincoln usage, the later Seventies saw C4 appear in the Ford Fairmont, Granada, LTD, and the Mercury Bobcat, Monarch, and Zephyr.
The C4 was occasionally used with a 351 Cleveland V8, specifically the M-code version. That usage required a larger bell housing and was available only from 1970 to 1971 in cars like the Ford Torino and Mustang, and the Mercury Cougar.
C4s are generally grouped into those made from 1964 to 1969, and examples produced between 1970 and 1981. Earlier examples used a 24-spline input shaft, which was upgraded for 1970 to 26 splines. The clutch hub was also updated in 1970 and had 26 splines of its own. The 26-spline clutch hub was very short-lived: It was revised the following year; downgraded to 24 splines.
Ford’s first alloy three-speed proved itself a simple and reliable automatic, which was fortunate given the vast spread of the gearbox within the Ford family. However, the C4 with its medium-duty limitations would not suffice for purchasers of the big V8 engines Ford offered throughout the Sixties. And so the heavier FX version of the Cruise-O-Matic was replaced by a newcomer for 1966: The C6, or SelectShift Cruise-O-Matic in marketing terminology.
Much like the C4, the C6 focused on simplicity, lower build costs, and less weight. Additionally, the old MX in particular was known for sapping an engine’s power, in a bad case of parasitic power loss. Larger V8 engines in the Sixties produced some big torque figures as they gulped down fuel, and the C6 was engineered to handle more torque than the MX.
Designed in the same basic way as the C4, the C6 used the same setup with a Simpson planetary gearset. It differed from the C4 in that it was the first automatic designed to work with a Borg-Warner flexible shift band. The bands replaced clutch plates and were intended to allow a longer service life and make the transmission more durable. Clutch plates were still used on low and reverse gears in the C6. The transmission’s plates and valves were made of tough composite materials, which meant the gearbox could wrangle up to 475 lb-ft of torque.
Unlike the C4, which used only two different bell housings (regular and 351M), the C6 had five different bell housings. They were designed to match with Ford’s various large V8 engine families, as well as the 300 inline-six. The six alongside the Windsor V8 and the 351 Cleveland V8 all used a Windsor bell housing pattern. The more powerful 351 Cleveland M-code, 400 V8s, and the 385 family (Lima) that included displacements of 370, 429, 460, and 514 cubic inches used the 460 bellhousing.
There was also an FE bell housing, for the line of Ford-Edsel V8s in production between 1958 and 1976. FE engine series displacements ranged from 332 to 428 cubic inches and spanned two different engine generations. Two other bell housing patterns were less common: One for diesels, and a special Lincoln pattern used only from 1966 through 1969.
The Lincoln bell housing was used only on MEL (Mercury-Edsel-Lincoln) V8 vehicles. The MEL was an engine built in Lima, Ohio that was replaced by the aforementioned 385 engine family. The bell housing was used only on Lincolns for three model years that had the 460 or 462 cubic inch engines. The bell housing was specially shaped on the passenger side to make room for the air conditioning box Lincoln used.
Early usage of the heavy-duty C6 included the Mercury Meteor, Cougar, and Comet, as well as larger engine Lincolns as mentioned above. Ford used it immediately in the LTD, the Thunderbird, the Fairlane, and the Galaxie. The C6 did not see as much model spread as the C4 but did advance during the Seventies into the Bronco, the LTD II, and the awful Mustang Cobra II. The C6 managed a long life as well but lived much longer than the C4. It saw usage all the way through 1991 in the Bronco, and through 1996 in the standard F-Series pickups. Heavy-duty F-250 and F-350 trucks used it through 1997.
In our next entry, we’ll finish off the Sixties with one final take on the original Cruise-O-Matic. It was a sort of Frankenstein designed to combine the best features of the original Borg-Warner automatic design.
Schmitt trigger on Jul 12, 2022
Excellent research you have done here, Corey. Looking forward for the next installment. A related, or perhaps unrelated question: were any of these transmissions ever used on Aerostars? I owned a 4.0L one, and if I recall correctly it had 4 speeds, although the top gear could have been an overdrive.
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