In This Guide
- C6 Vehicle Compatibility – Makes & Models
- C6 Transmission Overview
- Bell Housing Patterns
- Materials, Size & Weight
- Common Problems
- Remanufactured C6 Transmission Updates and Upgrades
- What’s Included
C6 Vehicle Compatibility – Makes & Models
- 1978–1991 Ford Bronco
- 1967–1996 Ford F-Series
- 1964–1970 Ford Fairlane
- 1966-1974 Ford Galaxie
- 1966–1980 Ford LTD
- 1977–1979 Ford LTD II
- 1966–1979 Ford Ranchero
- 1966–1979 Ford Thunderbird
- 1968–1976 Ford Torino
- 1966–1979 Lincolns
- 1966–1969 Mercury Comet
- 1967–1973 Ford Mustang
- 1967–1978 Mercury Cougar
- 1966–1972 Mercury Meteor
- 1968–1976 Mercury Montego
- 1968–1974 Mercury Monterey
- 1977 Mustang Cobra 2
C6 Transmission Overview
Produced from 1966–1996, the Ford C6 transmission is a heavy duty 3-speed automatic gearbox that saw use in some of the Blue Oval’s most popular models. It was called the “SelectShift Cruise-O-Matic” in the early days, and because of its ability to handle more torque than the C4 transmission, it was commonly used behind the big engines in full-size sedans and pickup trucks.
This was a completely mechanical automatic, so it didn’t have a lockup torque convertor or overdrive gears. The Ford C6 was also the first automatic transmission to be completely designed and built by Ford Motor Company. And it would eventually serve as the basis for Ford’s first electronically controlled heavy duty transmission, the E4OD.
The predecessor to the C6 was known as the Ford MX transmission (it was designed by Borg-Warner), and it was quite heavy (it actually had a cast-iron case) and complex. To address these issues without making their new transmission any larger, many components inside of the Ford C6 were made from powdered metal, and the transmission case was made from aluminum.
The new transmission used a much simpler 3-speed Simpson compound planetary gear set, and the C6 was the first autobox to use the Borg-Warner flexible shift band. Low and reverse gears used clutch disc plates, and there were also advanced (for the time) composite plates and valving. All of this gave the Ford C6 a maximum torque capacity of 475 lb-ft. Making it the perfect transmission for Ford to pair with their 351W, 351C, 428, 429, 460, and 462 gasoline V8’s. Along with the 7.3L diesel.
Bell Housing Patterns
Windsor / Small Block Pattern – 5-1/8” between top two bolt holes
Fits:
221ci / 3.6L V8
255ci / 4.2L V8
260ci / 4.3L V8
289ci / 4.7L V8
300ci / 4.9L I6
302ci / 4.9L (5.0) V8
335ci / 5.5L V8
351W ci / 5.8L V8 – 351 Windsor
351C ci / 5.8L V8 – 351 Cleveland
Cleveland / Big Block Pattern – 7-3/4” between top two bolt holes
Fits:
351M ci / 5.8L V8 – 351 “Big Block” or “Tall Deck”
400 ci / 6.6L V8
Ford 385 Engines –
370 ci / 6.1L V8
429 ci / 7.0L V8
460 ci / 7.5L V8
514 ci / 8.4L V8 (Ford SVO)
FE Pattern – 6” between top two bolt holes
Fits:
Ford FE Engines –
332 ci / 5.4L V8
352 ci / 5.8L V8
360 ci / 5.9L V8
361 ci / 5.9L V8
390 ci / 6.4L V8
396 ci / 6.5L V8
406 ci / 6.7L V8
410 ci / 6.7L V8
427 ci / 7.0L V8
428 ci / 7.0L V8
Diesel Pattern – Similar to the FE pattern, but not interchangeable
Fits:
420 ci / 6.9L Diesel V8
444 ci / 7.3L Diesel V8
Lincoln MEL Pattern – Similar to the FE pattern, but not interchangeable
Fits:
462 ci V8 – 1966-1968 Lincoln Continental
460 ci V8 – 1968-1970 Lincoln Continental
Due to its heavy duty design, the Ford C6 was used in a number of applications, including everything from the Ford Mustang Boss 302 & Ford LTD, to the Ford F-150 4×4 & Ford F-350 Diesel.
As a result, there were a number of variations to the case design, the pan, and the tail shaft. If you are planning to install a C6 transmission into a project vehicle, you need to make sure that it will fit your application, and that you’re using the correct torque converter.
This transmission is very popular for off-roading and drag racing, but it’s mechanical 3-speed design requires a lot of horsepower to operate. Which may reduce the fuel economy in road cars.
Materials, Size & Weight
In order to reduce weight, the Ford C6 transmission features a one-piece case design (the case and bellhousing are integrated), made from cast aluminum alloy. Over 10 lbs of powdered metal were used to make many of the internal components, which cut even more weight when compared to the cast iron Ford FMX transmission.
Thanks to these cutting-edge materials (for the 1960’s), the dry weight of a C6 transmission is 140 lbs, plus 30 lbs for the torque convertor. It requires 7-quarts of Type FA transmission fluid with the stock pan, plus an additional 2–4 quarts for the torque converter. The case length is 22-3/8”, but the overall length depends on which tailshaft housing is used – Ford cars: 14-in – Ford trucks: 7-in – Lincoln: 17.4-in.
Common Problems
No forward or reverse gear engagement
One of the most common C6 transmission problems is the complete lack of forward and/or reverse gears. The cause could be as simple as a low transmission fluid level, or a clogged transmission filter. But it could also be a stuck valve inside the valve body, a faulty torque converter, or the shift linkage may have become detached or broken.
Failed 1-2 upshift
If your C6 won’t upshift from first to second gear, then there could be a number of problems. It could be a bad governor, shift valve, servo, or one-way clutch. Many of these problems are related to age and mileage. However, shift kits and other upgrades will significantly increase the service life of your transmission.
Slipping in, out of, and/or between gears
Probably the most common C6 transmission problems are slipping between the gears, out of gear, and the hesitation to go into gear. The first thing you should check is the fluid level. If there is too much or too little transmission fluid, this problem can occur. It could also be a blocked transmission filter, a transmission pump problem, a bad vacuum modulator, a faulty torque converter, or an improperly adjusted transmission clutch / transmission band.
Ford C6 Shift Kits
If you need more performance from your C6 than the stock setup will provide, then you should consider a Ford C6 transmission kit. These are modification packages for the valve body, and are typically available in towing, performance, or racing specification.
Each one contains parts that will change the line pressure, so the transmission will have more holding power for the bands and clutches. Thus preventing slippage during extreme use conditions. Race-specific input / output shafts and hardened planetary gear sets are so available.
I have a 1988 ford f350 with a 7.3l idi and just replaced the motor had to remove the transmission to repair the flexplate it sheared off everything was reassembled fluid was added and now im experiencing not dropping into gear have to have rpms around 2000 to finally engage once its driving it will shift just fine its only from dead stops my next thing to go after is the trans filter if that doesnt do it im out of ideas it nevr did this before i pulled the old motor out i have a c6 transmission
hard trans shifting in all gears
late winds out
I have a 88 f350 has 7.3 turbo I believe has c6 auto i blew a tire and in that in one of tranny lines made a hole in it well long story short park goes forward reverse goes forward about 5 ft then it stops and kills the truck everything else is forward can u help me please send a email
C6 transmission wont shift from 1 to 2
Did you ever figure this out? Having the same problem
I am having an issue with my 1973 F250 not wanting to stay in park. Along with this problem getting progressively worse as time goes on. I am now having to hold hard pressure to the left on the shifting arm in order to get the ignition to engage. One additional symptom that actually was the first I noticed was that the reverse lights failed to come on when backing up the truck. Fluid level and color both look good.
This seems to me like its probably a linkage adjustment but Im no expert. So any input and/or advice would certainly be gratefully accepted as well as sincerely appreciated
There’s no problem the is that I had someone help me take the transmission off and he said take off front seal and front hub input bushing replacement and Now can find the front pump bushing.. I didn’t know that you have to take off front bushing . Knew about front seal .so now I am looking for a New transmission cause I don’t want any problem with leak from seals . .
1972 F250 390 C6……..hunts between 1st and 2nd in crawling traffic after warmed up, sloppy, noisy, unsure shifts, literally flopping between gears.. But only when warmed up and in crawling traffic for a bit. First rebuild had same problem as original trans, so had an entirely different core built by reputable builder. Same problem…hotter days problem comes on sooner. Weird. Modulator adjustment changes shift points in general, hasn’t affected this problem. 17″ vaccuum. Ideas?
Get a TransGo shift kit and put it in the valve body. There are different levels of shift firmness to choose from and it will end the hunting. Alternate fix is to hook your vacuum modulator to ported vacuum on the carb which will delay the 1-2 upshift to about 20 to 30 MPH depending on the modulator itself and it’s adjustment. I prefer the black band modulator as it increases the road speed upshift timing so it stays in low longer.
My transmission was leaking in the front seal and I am thinking of rebuilt the transmission. Cause I don’t want to be taking off the again. One time is enough off talking the transmission. So now I looking for someone to rebuild the transmission. Is there anyone out there who wants to rebuild my transmission
82 f150 302
Shifts hard into 2nd and 3rd and sometimes doesn’t shift to 3rd
1971C6 not shifting from second to third. Other shifts okay incl reverse. Kick from 2nd to 1st okay.
Also, how important is Type F fluid over Dexron type? Is F more viscous?
Second to third failing to upshift is controlled by the governor mounted on the output shaft. Dirty or stuck valves or low fluid pressure from the pump is the common cause but if the vacuum modulator has been turned in too much it will prevent upshifting until very high RPM. When rebuilding a C6 always use dexron 3 or 5. New clutch materials are fine to use the newer fluids which have better lubrication properties and lifespan.
No forward gears
.just rev
Will not shift from 2nd to 3rd 1988 F150
Leaking trans fluid especially when parked with rear of truck higher than front
It was shifting . I added fluid now only drives hi and low 4 wheel drive lookup positios…hums in 2 wheel drive attempts
hesitate when shifting in to third gear
Just Rebuilt my c6 in my 78 and it’s taking off in 3rd when I put it in drive. I can manually shift into first. What did I do wrong?
don’t be too concerned about this it will come out of it, just make sure when it starts off in 3rd blip the throttle and it should engage 1st if not either manualy shift it down or stop and try it again. It will correct itself after doing this a few times.
Valve in governor is stuck. Put on jack stands and idle in reverse for a few minutes. It tends to flush out the crud. Then drive forward at 2 or 3 MPH and put in park. I know it sounds crazy but it won’t hurt the parking pawl and the vibration from the pawl will usually unstick the governor if the reverse flushing didn’t. Other wise, pull the tailshaft housing and remove the governor and clean and reinstall.
I have a vibration will a new toquecvter and flywheel fix the problem
purchased new converter for C6 trans and it Does not set into the housing far enough to bolt trans to motor ? Any thoughts????
Wont go into reverse or drive until warm up
I Rebuilt mine because it wouldn’t engage into drive until about 10 minutes after starting. I found clutches with missing teeth and warped from heat.
Won’t go into drive until warm up
67 ford c6 leaking out the shift shaft.