Transmission Selection Guidance

Clutch, transmission, rear axle

Moderators: FORDification, 70_F100

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ZeroBurn07
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Transmission Selection Guidance

Post by ZeroBurn07 »

So I am in the middle of a restoration of my 69 F100 SWB and I am looking for advice. I have a 351C that runs pretty strong but is currently tied to an FMX cruisomatic transmission. Which is a 2 speed with overdrive from what I've seen. So while I have it all apart and preparing everything I'd like to find out what would be a good swap for that FMX. When the truck was purchased it had a floor shifter and my donor steering column/wheel doesn't have the shifter on it. So I was thinking that perhaps I would leave this a floor shifter. So then it started running through my mind that maybe I should make it a manual transmission... or perhaps a decent/strong auto transmission. So I've looked up so many solutions that it's left my head spinning. Just thought I'd ask and get some responses. I don't know what gearing is in the rear end.. and I'm changing/swapping plenty of things.. so right now is the best time to make the change. Thoughts?
ultraranger
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Re: Transmission Selection Guidance

Post by ultraranger »

The FMX is a non-overdriven transmission. It's 1:1 in high gear just like a C-4 or C-6 although, a C-4 and a C-6 has a slightly better 1st gear ratio of 2.46:1.

FMX Gear Ratios:
2.40:1 1st gear
1.47:1 2nd gear
1.00:1 3rd gear
2.20:1 reverse

If you have a 351C, a Ford 4R70W 4-speed automatic overdrive transmission from a 3.8L, 4.2L or 5.0L Ford engine will bolt up (a 4R70W from a 4.6L/5.4L engine will not bolt up). The 4R70W came out in 1993 but the best versions are from 1998-up. It will be more expensive on the front end to install, since it will require a stand-alone shift controller but, it's a far superior transmission to the old AOD. The 4R70W has a wide ratio gearset: a MUCH better 2.84:1 1st gear, 1.55:1 2nd, 1:1 3rd and a .70:1 overdrive in 4th.

There's tons of information on the internet about the 4R70W.
Steve

1969 SWB F100 Ranger. 240-6, C-4, 9" N-case 31-spline Traction-Lok w/3.50 gears.

1968 Mustang. My high school car. Owned since 1982.

2003 Azure Blue Mustang Mach1.
rollercam1
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Re: Transmission Selection Guidance

Post by rollercam1 »

The 4R70W is a great transmission! The overdrive is so worth it. I went with the C-6 for the strength. The cost of a manual was more than what I wanted to spend on this project to get into an overdrive. So, I second the 4R70W. The C-6 set up is brutally strong though. As it is with everything, budget will decide most.
ZeroBurn07
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Re: Transmission Selection Guidance

Post by ZeroBurn07 »

Interesting.. I didn't even have that transmission on my radar. I dig further into that and do some research.
ultraranger
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Re: Transmission Selection Guidance

Post by ultraranger »

Steve

1969 SWB F100 Ranger. 240-6, C-4, 9" N-case 31-spline Traction-Lok w/3.50 gears.

1968 Mustang. My high school car. Owned since 1982.

2003 Azure Blue Mustang Mach1.
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