• 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Transmission, what should I do?
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.
(01-31-2020, 01:09 AM)Spike Morelli Wrote: 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 Smile
(02-01-2020, 12:35 AM)mrxerox Wrote:  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.
Yeah, I guess my exhaust could be considered a little on the louder side Smile 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.
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.
I switched to a top loader from the FMX. The hardest part was the Z-bar installation.
Share Thread:  

Possibly Related Threads…
Thread Author Replies Views Last Post
  C6 to aode transmission swap Scottyhudson 3 173 02-12-2020, 12:51 AM
Last Post: Don C
  Transmission cooler line nut is broken n_reckless 10 592 10-22-2019, 10:40 AM
Last Post: Mister 4x4
  1973 FMX transmission conversion JULIENHATSWELL 9 933 05-21-2019, 07:32 AM
Last Post: Omie01
  Transmission advice Tataocb 24 2,171 04-13-2019, 04:12 PM
Last Post: Don C
  C4 Transmission - Missing Kickdown ? Parkka 3 452 04-09-2019, 07:29 PM
Last Post: Hemikiller

Users browsing this thread: 1 Guest(s)