Whats the deal with FMX's ???
 

Do any shifter manufacturers (hurst, b&m) make any aftermarket shifters for the FMX auto transmission? Does anybody make any custom shifters for them in the style like the "Megashifter" or a race shifter?

As far as i know, theres nothing for the FMX, unless i pay 200+ dollars for a complete custom shifter, the kind that they have in hot rods (the single stick thingy), Those things are ugly and i want something comfortable.

And why do many header companies say that their 351c 71-73 mustang headers wont fit with an FMX auto? i know a guy with a 73 grande 351c 2v , who put the headmans (they say it will only fit around a c4) in and there was no problem... There is so much i dont know about the fmx, theres no info anywhere on it that i know of.

All the factors ive seen so far point out that the FMX is a lost cause, throw it away and get a c4, kinda transmission. And changing trannies is one thing that i cannot afford or do anytime soon! Im only 16!

Thanks for all your help!

Sorry, but I can't help you with the shifter or the headers, but I can tell you that I've heard the opposite about the FMX trannys. I've always been told that they can handle more power than the C-6's, and that they're strong. I know you can't always believe what you hear, but I'm just giving my limited knowledge (or hearsay). I'm sure someone here will know quite a bit more about them (REV?).

Just wanted to say nice car, if thats yours in your avatar.

Being a fellow FMX owner I feel your pain about not getting an aftermarket shifter, but this tranny is just not as popular as the C4 or C6. It is not because of how durable it is more because of the weight difference and parts availability. My advice is to run it until it drops and then switch to a C4 or AOD. As far as the header fit, the transmissions are not that different especially to a C6.

I too feel your pain.

As for headers, I have 1 3/4 headers on my 351C with an FMX. I was thinking they were from Headman but I am not sure. I bought them through summit. I really wanted the 1 5/8 but ran into the same problem and didn't have the guts to order the ones listed for c4 only. Really annoying since 351's never came from the factory with the c4.

As for durability, the fmx is very good. My understanding is the durability went c4, fmx, c6. But I know several people who swear by the fmx. The downside is weight. The fmx is a cast iron case where the c4 and c6 are aluminum. I am waiting for my leaking fmx to die so I can replace it, but I am afraid as long as I keep pouring oil it it, it just won't die. Guess I need to get more HP.

I have seen a shift kit for the fmx but that is it. If it were me (and it might be) I would replace it with a c4 or c6 down the road. Just because of parts availablility. If you are gentle with closer to stock hp and don't race, I think the c4 is the way to go. If you want bullet proof, go c6. I am thinking of getting a c4 with upgraded clutch materials myself.

You are probably tired of reading, I am tired of writing. Good Luck

Thanks for your info guys, i had no clue the FMX was stronger. When i bought the car i had never heard of an FMX, and i thought it was a prototype, only one ever made is on my car and i cant do anything with it!! :D lol. ...

Where can i get the shift kit, and is it expensive? I have no how the shift kit helps or what it does.

And as for my avitar, it took me untill now to figure out how to get my little picture thingy under my name, ahahha i saw a button in my user cp and i decided to click it. I had no idea what an avitar was and holy crap! i can put my cars pic in there now. My website (in my signature) has tons of pics of my car, including the one in my avitar. Also pics of my friends cars.

Hey guys with FMX's, i just noticed something, when im running in 1st gear, and not in DRIVE, it makes a bit of noise (doesnt sound bad), just a bit of humming, when im going like 10 or 15 mph, at about 800 rpm. Is that normal? Or is it bad for the tranny to do that? I wanna know so i dont break anything! hehe thanks.

Oh and when i have it in DRIVE, when im going like 15mph, it already shifts into 2nd! It shifts really really early everywhere unless im stepping on it. My friends falcon with a c-4 always shifts at about 2000rpm or 2500rpm in drive. Just curious.

It sounds to me like you have a normal sounding FMX. Keep running it and check with local transmission shops for a shift kit.

Adjustable vacuum modulator for C-4
 

The C-4 has an adjustable vacuum modulator. I always have to play with mine a bit to make the the shift points the way I want them. It only affects part throttle shift points, not at WOT that is set by the governor.

Not sure about the FMX, as I have no experience there. Clark might know.

Rev

FMX was similar to Cruise -a- matic. Except no rear pump.
Cast Iron mid section too.
The noise is the plantaries whining. Pretty normal.

Fairly strong trans. Drive it till it goes and change to an AOD or C-4.