What is the better trans, C6 or FMX

John in Oz

John in Oz

Well-Known Member
I have been looking around for a while for a trans for my A project which is getting an FE engine because I already have it. A guy has advertised over here that he has a C6 trans but upon looking Google FMX and C6 it would apear that it is in fact an FMX. His add says it is to suit an FE but he is advertising it as a C6 but after looking around I think it is in fact an FMX. $400 with converter and needs rebuilding.

Does anyone have a comment on which of these is the better trans to use.
 
C6 and AOD both are aluminum with cast-on bellhousings.
C6 and AOD may or may not have ribs.
FMX has bolt-on aluminum bellhousing / cast iron body / aluminum tail shaft.
C4 has bolt-on bellhousing / all aluminum.
FX and MX were all iron .. I think...

Found this blurb John ........

The Ford C4 was a three-speed, light-duty automatic transmission introduced in the 1964 model year and produced through 1986.

It featured an aluminum alloy three-piece case ( bellhousing, 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). B
By comparison, the 351 Windsor and 351 Cleveland small and intermediate-block engines were backed by the medium-duty FMX.

The FMX used stronger MX-type rotating parts in the smaller FX case; introduced in 1968 and built until 1982 at the Fairfax plant, which closed when the FMX was balanced out.
The FMX used a Ravineaux planetary gearset.

The Ford C6 transmission was a heavy-duty automatic transmission built by the Ford Motor Company between 1966 and 1996 for use with large, powerful big-block V8 engines.
It was very similar to the C4 transmission but could handle greater power.
It was used primarily in trucks, although it was also used in some larger cars with big block engines, such as the Ford FE engine and Ford 385 engines.

Among the performance crowd, the C6 is the best and most desirable. The FMX is probably the rarest in general, but it was not used in cars.
Some parts might interchange between the C4 and C6, but doubtful on the FMX.
 
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Thhanks Bullet, I feel that it is really the C6 I am after but they are hard to come by down here, one will turn up though. Thanks for that. Then again I could always go a manual ......... nahhh I like to build the car so anyone can drive it. I had a 32 roadster years ago with a Top Loader and then fitted a C4 behind the 351 Cleveland and it made a lot of difference for other folk driving the car. But at the same token this FE might develop some reasonable H.P. so I want a strong trans to.
 
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The FMX trans roots date back to the Ford-o-matic back in the 50's. Cast iron case and man they weighed a ton.

For any performance build and easily available parts go with a C-6.

Interesting to note that the C-6 parasitic losses are about 50-60 hp and the FMX is about 25-30 if that matters at all.
 
Thanks for that information, I had to google the different transmissions to make sure which was which and the one advertised is an FMX, I think I will wait until a C6 comes up.

Thanks again, John
 
The C6 is a three speed automatic

The AOD is a 4 speed automatic with an overdrive.

Dry Weights:
FMX 160 lbs
C4 110 lbs
C6 140 lbs (stock converter = 31 lbs
AOD 150 lbs (stock converter = 34 lbs)


Measurements:
Trans Bellhousing
Face to Trans
Mount Length Overall Length
From Bellhousing
To Tailshaft End
C4 20¼-inches 30½-inches
C6 22½-inches 33½-inches
AOD 22¼-inches 30¾-inches
E4OD 29 3/8-inches 37½-inches
 
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Brian what is the story with the AOD, would that bolt straight onto and FE and what did these come out in, I could run lower diff gears then with the over drive for the highway, not that it really makes much difference to a light weight model A anyway.

Thanks for the info guys. John
 
From Wikipedia

The AOD was intro'd in 1980 and can be found in:

1980–1986 Ford LTD
1980–1993 Ford Thunderbird
1980–1993 Mercury Cougar
1984–1993 Ford Mustang
1980–1986 Mercury Marquis
1980–1987 Lincoln Continental
1980–1983 Lincoln Mark VI
1983–1993 Ford Econoline
1983–1991 Ford LTD Crown Victoria
1983–1992 Mercury Grand Marquis
1982–1993 Ford Bronco
1981–1992 Lincoln Town Car
1980–1987 Lincoln Continental
1980–1983 Lincoln Mark VI
1984–1992 Lincoln Mark VII
1992 Ford Crown Victoria
1980–1988 Ford F-Series

Gear Ratios:
First: 2.400:1
Second: 1.467:1
Third: 1.00:1
Overdrive: 0.667:1
Reverse: 2.00:1


After 1992, the AOD was redesigned with electronic controls to become the AODE.

As to bolting up too an FE, will check and advise.

UPDATE:
There is an adapter that will allow you to bolt a late model AOD onto a 390 FE and reap the benefits of having an overdrive. Check "AOD.com" or "FordAOD.com"
Lots of info.

Adapters available from:
www.transmissionadapters.com/ford_fe.htm
 
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John,
If you need measurements or pics of an AOD I have one in my shop I was going to use behind a 302 but changed plans so it's sitting on the floor.
 
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