Jump to content

Transmission, what should I do?


Recommended Posts

I've got an FMX with over 120k miles and it's leaky and shifts kind of rough.  I've got a few options:

-Rebuild FMX

-Swap in a C4 or other manual transmission

-Swap in AOD transmission

 

I'm planning on adding some power to the engine through a new intake, carb, and maybe cam.  Originally I wanted to go with a manual transmission, because I love driving manual cars, feels more engaging.  Then I considered sticking with rebuilding the FMX might be the best route for now.  Now I'm seeing a lot of cars going to AODs.  Any advice, suggestions?

73' H-code Convertible

351C 2V

FMX automatic

Link to comment
Share on other sites

I went from a leaky C6 to a manual TKO600. The options really depend on your budget. I love my combo. No regrets. You can look at my build thread for the details.

 

Sent from my SAMSUNG-SM-G930A using Tapatalk

20160929_171923_edit2_small.jpg

 

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump

Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes

Link to comment
Share on other sites

I've got an FMX with over 120k miles and it's leaky and shifts kind of rough.  I've got a few options:

 

-Swap in a C4 or other manual transmission

 

Any advice, suggestions?

The C4 is an automatic.

 

Another option is a Gear Vendor overdrive behind your rebuilt FMX or a C6.

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

Link to comment
Share on other sites

I've got an FMX with over 120k miles and it's leaky and shifts kind of rough.  I've got a few options:

-Rebuild FMX

-Swap in a C4 or other manual transmission

-Swap in AOD transmission

 

I'm planning on adding some power to the engine through a new intake, carb, and maybe cam.  Originally I wanted to go with a manual transmission, because I love driving manual cars, feels more engaging.  Then I considered sticking with rebuilding the FMX might be the best route for now.  Now I'm seeing a lot of cars going to AODs.  Any advice, suggestions?

I would ask yourself what you really want. An Auto or a Manual. If you would be happier with a manual then no point sinking money in the FMX or another auto. You're running 2V heads and adding an intake and 4bbl carb. Stock Cam? If it is a mild engine you could do a T5 swap pretty cheap. I did that and have been extremely happy. Even with the significant engine upgrades I have done since the swap the T5 is holding up just fine.

73 Grande H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

 

- Jason

 

 

082-hot-rod-power-tour-2017-1970-1970s.jpg

 

Link to comment
Share on other sites

  • 1 month later...

The FMX is a pretty tough trans, worth keeping, but it doesn't get the respect it's worthy of for some reason with most people. In our cars they're found behind a 351c ( 2v ). In '70, the FMX was behind the 351c 4v, in '71 the C6 was being put behind the 4v, but that doesn't mean the FMX is not up to the grunt. If you should decide to keep it, a company called "Trans-Go" offers re-programming kits, ( shift kits), that really wake the FMX up. Firmer shifts and longer trans life are key selling points, and, I believe they offer a few different levels of performance kitting. Along with an AUX trans cooler, I run one, and it was well worth doing.

  • Like 1
Link to comment
Share on other sites

I too did the swap to a manual. I'd never go back to an automatic willingly.

 

What do you really want? Does that suit what you plan to do with the car? Base your decision on what's best for your situation.

 

Any PROPER hot rod NEEDS 3 pedals!

  • Like 1

[align=left]Jeff T.

 

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passengers. [/align]

Link to comment
Share on other sites

Any PROPER hot rod NEEDS 3 pedals!

 

Totally agree - which is why our C4, C6, FMX, and AOD-equipped cars are perfect:  Gas Pedal, Brake Pedal, and E-Brake Pedal.   :whistling:

 

 

 

rofl :cool: rofl :cool: rofl :cool: rofl

Eric

mach1sig2.gif

Link to comment
Share on other sites

Not sure why anyone would ever choose a C4, C6 or FMX when there are TONS of 4R70W transmissions out there for dirt cheap that are a bolt in affair and will withstand 500+ hp with a mere valve body kit install. Add a boneyard explorer driveshaft for $100 and change the chuck end and its a drop in as well. A member of the forum (premiergenerator@gmail.com) sells a kit with a bolt in rear mount that clears performance exhaust and even has a linkage rod to use the stock shifter. The Baumann controller is not cheap but worth every penny to have the overdrive. 3300+ rpms any time you are on the highway going 60mph gets old fast. I am in the process of the swap now and cant wait.

Link to comment
Share on other sites

The FMX is a pretty tough trans, worth keeping, but it doesn't get the respect it's worthy of for some reason with most people. In our cars they're found behind a 351c ( 2v ). In '70, the FMX was behind the 351c 4v, in '71 the C6 was being put behind the 4v, but that doesn't mean the FMX is not up to the grunt. If you should decide to keep it, a company called "Trans-Go" offers re-programming kits, ( shift kits), that really wake the FMX up. Firmer shifts and longer trans life are key selling points, and,  I believe they offer a few different levels of performance kitting. Along with an AUX trans cooler, I run one, and it was well worth doing.

 

Couldn't agree more . I'm building one at present to go in an F truck with a 393. 5 clutches in each pack, solid bands relined in red , Transgo 37-1 kit and 9" billet case custom built converter

 

Back in 2004 I built a nice 550HP 502 for a friend , he already had FMX so we went with it .. It's still there today has been very good :)

Link to comment
Share on other sites

 3300+ rpms any time you are on the highway going 60mph gets old fast.

 

Maybe.....I used to own a '66 GT-350, and that little jewel really didn't show off UNTIL 3000 rpm, and higher, to around 6000. Believe me, It never got old.  Today, my '71 Mach 1, running 3.50 gears in the back, is turning approximately 3300-3500 at 70 mph on the freeway, and it's not a big deal. I mean, isn't one of the Cleveland's strong points it's breathing capability? To be honest, I think the steady rpm thing is mostly irritating to those with loud, modified exhaust systems . The sound level inside my car is very low, as I've been very happy with the duals, cross-over tube equalizer, and dual Huth "turbo mufflers", out the back through the valence tips.

Link to comment
Share on other sites

Yeah, I guess my exhaust could be considered a little on the louder side :) I guess what I am saying is that for close to the same money you can have AODE with bolt in parts out of a junk yard that is plentiful in supply and will easily handle the power level that most here are at or want to be at without hacking up the car at all. Whats not to love? The controller is a little spendy but to have all the options is gives you is a no brainer IMO.

Link to comment
Share on other sites

Mrxerox,

You might know this better than I, but, I seem to remember back when I worked at a Mustang restoration shop, that guys retrofitting an AOD trans to their early Mustangs had shifting troubles with stock rear end gearing. Have you encountered this, or , is there any truth to this? It was some years back, but I think the fix was that the AOD required lower rear end gearing ( higher numerically ), than the factory automatic gearing to shift correctly. Sounds counterproductive, I know, but, I thought I'd heard this.

I've no experience with any overdrive trans, and don't know anyone personally who has made the swap, so I'm open if someone wants to take me to school.

Speaking of rear end gearing...….and since I'm an O.G..( old guy ), I remember when low rear end gears were commonplace on the street. Ratios like 3.91s, 4.11s, and lower, were in lots of street driven cars, like hot rods, and factory muscle cars, especially if they were stick shifts. Four speed sticks were considered mandatory on a for-real hot car back then. Exhaust wise, that generation of enthusiasts would many times, just have something as short as glass packs bolted directly to their headers, with turn-downs , ending somewhere from under the front seat to just forward of the rear axle. Ah,....to be 18 again, our cars were loud and in your face, and gas was cheap. Those were some days , but for me, driving my car as much as I do, daily, with an automatic trans and power brakes, and a cam profile that won't kill off vacuum, and therefore peaks at a lower rpm than a stick car, the 3.50s that I run are probably as low as I should go these days.

Link to comment
Share on other sites

  • 8 months later...
On 12/5/2019 at 9:37 PM, Don C said:

The C4 is an automatic.

 

Another option is a Gear Vendor overdrive behind your rebuilt FMX or a C6.

I've decided on rebuilding the FMX and I'm going to look into overdrive, although I don't know anything about it.

I should note that I know very little about transmissions, but I'm going to read other posts in this forum to get a good idea of what to do.

Thanks for the help everyone!

73' H-code Convertible

351C 2V

FMX automatic

Link to comment
Share on other sites

To rebuilt a FMX by yourself is not like a walk on a sunny afternoon. If you really want to rebuilt the FMX by yourself, search for Kenneth Collins or badshoe productions. He can supply footage, how to do it. It isn't cheap but it's worth it. I've learned a lot from this guy and at the end my FMX works better than before. 

Just my 2 ct.

Cheers Frank 

1972 Mach 1, 351C-2V, wimbledon white, blue all vinyl luxury

born in Dearborn, grown in the district of San José, spent a lifetime in California, moved to Germany in 2010

Mustang_Mach1_wallpaper_300_150.jpg proud member of clublogozusammen.JPG.59fb4a10d15cfff9ec756235059135b8.JPG

Link to comment
Share on other sites

40 minutes ago, Vicus said:

To rebuilt a FMX by yourself is not like a walk on a sunny afternoon. If you really want to rebuilt the FMX by yourself, search for Kenneth Collins or badshoe productions. He can supply footage, how to do it. It isn't cheap but it's worth it. I've learned a lot from this guy and at the end my FMX works better than before. 

Just my 2 ct.

Cheers Frank 

Chiming in here, but does that mean you have decided NOT to go with the top-loader conversion? Just wondering.

Geoff.

 I learn something new every day!

Link to comment
Share on other sites

Geoff

After two seasons with a not running car I didn't want to lose another year. Therefore I postponed the installation of the toploader. This does not mean that I would ever sell the toploader again. It will surely still find its way into the Mustang. I had a lot of fun and drove over 2,500 miles this year.

Frank

1972 Mach 1, 351C-2V, wimbledon white, blue all vinyl luxury

born in Dearborn, grown in the district of San José, spent a lifetime in California, moved to Germany in 2010

Mustang_Mach1_wallpaper_300_150.jpg proud member of clublogozusammen.JPG.59fb4a10d15cfff9ec756235059135b8.JPG

Link to comment
Share on other sites

@Vicus oh yeah BIG +1 for Ken.

He gets from me the gold crown when it comes to support!

I’ve restored and improved the C6 for my 429 and it was almost a walk in the park thanks to his guidance. Already been in contact with him for the AOD swap that I’m prepping for my 73 to replace my FMX. While I like the fmx, I’m used to my t-bird’s AOD low rpm’s and want the same on the mustang. 
not to mention fuel costs are ‘bits’ higher here, where we pay more for a liter than you guys do for a gallon... 

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...