FMX to 4r70w swap

[jorgem2]

Just completed the tranny swap from an FMX to a year 2000 4r70w and high stall converter. I used a manual shift valve body and a racing converter sourced from the clickclick racing forums. It can be also adapted with an electronic controler if you want to retain auto shifting. I didnt want to mess with the electronics and tuning so took the easier route.

The 4r is 1" longer so the mount is farther back, the unusual thing is I was able to modify my existing crossmember and a few other things to make it work. And look semi stock appearing, even reused the original shifter and linkage.

I have a souped up cleveland and 4.10 gears and I got tired of driving on the highway at 3500 rpms while the mini vans passed me. The overdrive and electric lock up are the reason I chose this tranny.

The other reason was to have a 4000 rpm stall converter and be able to lock it up via a switch for cruising eliminating the slippage and heat that comes with it.

Here are a few pictures

4r70w from 2000 v-6 mustang with 4k stall converter

FMX is out

Chopped forward ear and front section off, this weakens the x member, so I added gussets and boxed it in from underneath. also reinforced the factory welds which are spot welds.

I slotted the holes as far as I could to allow more adjustability on the crossmember. Then I cut this bump off the rubber mount and flipped it which also gained some room then slotted the mount as well and used allen head bolts since the new holes are now close to the wall.

Here it is installed showing the wires that shft OD and lock up, I installed the switches on the forward wall of the ashtray so when I close the lid the car looks stock.

I changed the rear yoke to a 1350 series I found at a junkyard because the 71-73 use a funky and small yoke, this gave me more driveshaft options as well as strength. The yoke was the same lenght as the original so I needed a 50" center to center driveshaft. I got lucky and found one at the junkyard that was 50 1/4" long.unfortunately I dont know what ford vehicle it came out offor reference, maybe a truck with a larger tranny.

Last night I was buttoning up the drive shaft and was so desperate to run it but my muffler was hitting the driveshaft and I lost my patience to get it running. So I need a new muffler now.

I didnt like them anyways, so I will upgrade them soon.

I should probably make a list of parts needed for the swap and such before I forget

 

[TommyK]

Very nice. O/D is on my wish list.

 

[mach1460]

awesome swap, is there any difference in strength when it come to the 4r70ws? I know they were offered in trucks as well as mustangs, would the truck transmission be any stronger than the V6 mustangs?

 

[jorgem2]

I have read a 4.2L truck tranny has one extra clutch plate but the tranny may be longer overall. Also read that you can just add the extra clutch disc to the V-6 tranny.

The problem with the truck tranny is its hard to find one with low miles and an easy life, I found the V-6 tranny that had low miles and was spotless inside so I used it as is without rebuilding to save costs.

The years to get are 98-2002 just make sure they have a speedo spline on the tailshaft.

 

[mach1460]

very cool, im surprised that the 4R bolted up to the cleveland with out an adapter plate of some sort. Same bellhousing bolt pattern. If im not mistaken, the 351C and the 429 are the same bolt pattern for the bell housing. just wondering if the 4R would hold up behind my 532....

 

[jorgem2]

351 C is same as small blocks, it wont bolt up to the big blocks.

I did read that you can use an E40D truck tranny posibbly. I think it was 460ford.com

 

[cobra3073]

Yes, MACH1460 you were probably thinking of the 400 which has the same bolt pattern as the 429/460.

I don't know if the 4r70w (even with the modifications) will hold up to your Stroker big block, especially if you are getting into it.

BT

 

[mach1460]

So far my c6 is holding up, even with the slicks. Thing is a rocket with the slicks. It sure would be nice to have one more gear... Maybe someday.

 

[mach1 fever]

what flexplate did you use? the cleveland is 28 oz.balance and correct me if im wrong were not the 4r70w's used with 50 oz flexplates?

so were you able to use the felxplate from the fmx (28 oz, ) or did you go aftermarket?


also isnt the dish on the two flexplates different, the fmx being more dished and the 4r70w more flat surface?

just asking what you did . thanks

 

[jorgem2]

The original 351C/FMX flexplate fits perfectly on the V6 4r70w converter.

Or you can purchase an aftermarket flex for your motor as long as it has the common 11 7/16" converter bolt circle

 

[mach1 fever]

The original 351C/FMX flexplate fits perfectly on the V6 4r70w converter.

Or you can purchase an aftermarket flex for your motor as long as it has the common 11 7/16" converter bolt circle

good info and thanks for responding.:runninpony:

 

[Darkhorse71]

How do you like your Manual VB from silver fox? Shift well? Too firm? Just right?

 

[jorgem2]

At slow speeds on the street the loose converter makes the shifts pretty soft, sometimes chirping second when I let the revs build. 3rd 4th and Overdrive shifts are all firm but not harsh. But once I floor it and let it rev the shifts are very strong,

So far I am happy with it, just install and go.

I think you can get 2 different shift calibrations, I asked for hard shifts for racing.

 

[FasTnNefariouS]

Sounds like an awesome swap, but if it came from a V6, then it can't be tougher than a T5. I spoke to someone at Modern Driveline and was told not to use the T5 with a 351C 4v motor. They say it can be done, but not recommended. Any issues since the conversion? BTW, awesome job on the crossmember!

 

[Mesozoic]

Sweet buildup! I've been researching the 4R70W transmissions for some time now... the later model units as you suggested (98-2004) have the best parts inside. Even the V6 transmissions are 500 hp capable, apparently.

I've got a B&M street/strip C6 in mine at the moment with a 3000 RPM stall converter. It drives wonderfully, really, but highway is annoying. Part of the reason I swapped in an EEC-V computer for my fuel injection is that the transmission controller is part of it. Fully tunable and adjustable shiftpoints, lockup points, etc. I'm going to move forward with the OD, for sure.

I've got a few major concerns before I start, though. The harness from my computer to the transmission is from a '96 Crown Vic and I know there was a minor pinout change in connectors between the earlier and later 4R70Ws. The other issue is where to source a good torque converter from? I see that B&M makes a Holeshot 3000 for the 4R70W, but it is pretty expensive! If it's a good unit, I'll consider it, but I thought there might be some more options.

 

[InjectedMach]

I make a laser cut 3 piece kit for this swap, new crossmember, shift rod and range selector mount.