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Discussion Starter #1 (Edited)
Have option to purchase a 4R70W out of a 96 Mustang GT to swap into my 95 Mark VIII.

Anyone know if this works?

case: F7ap-7006-AA
placard: f6zp 1996-97

any insight is appreciated.

thx.

Jim
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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You will need to swap your TCC solenoid and MLPS and change to the appropriate speedo gear for your tire size/rear axle ratio; the Mustang has an 8 tooth output shaft and the Mark VIII has 7. Most likely 19 teeth if you have a 3.08 (or 20 with a 3.27).
 

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Discussion Starter #3 (Edited)
You will need to swap your TCC solenoid and MLPS and change to the appropriate speedo gear for your tire size/rear axle ratio; the Mustang has an 8 tooth output shaft and the Mark VIII has 7. Most likely 19 teeth if you have a 3.08 (or 20 with a 3.27).
Thanks Brandon - If I'm swapping out those (TCC solenoid and MLPS & speedo gear), would it be better to switch to a newer tranny?
 

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The 95 is about the worst trans you can have, and a number of improvements were made with 96, again in 98, then 99. To "turn" the 95 into what it should be you'd need (as a starting point) a new valve body, mechanical diode, stub shaft, filter, pan, accumulators, seals and all the frictions.

However with your 96 coming out of a Mustang, you can count on its being abused so it should be gone through and rebuilt before you install it anyway. Taking that a step further, you should just get a newer core from 99-03 or so (after that they started using turbine output shaft sensors instead of a gear), since it's going to be about the same price as the 96, and have it reworked instead. While that's being done you can swap your OSS into it too so you have a wider selection of speedo gears/rear end ratios available.
 

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Discussion Starter #6
Sorry for the follow-up stupid questions.
  1. If I got a 99+ tranny, would it be a similar exercise of swapping out the TCC solenoid and MLPS + OSS, or much more involved?

  2. Also - would I look for specific ones or just stay away from the 4R70Ws that came out of trucks?
Don't know if it makes a difference, but I have an LSC model.
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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With the LSC you've got a 3.27 rear end so swapping your OSS to the new trans a good idea because you're more or less at the upper limit of what rear end the available speedo gears can support. Depending on your tire size you might be able to get away with a 3.55 with a 21 tooth, but 3.73 is off the table unless you want to get a SpeedCal because the 23 tooth gears are known to self destruct on a semi-frequent basis.

You will need to swap the MLPS and TCC solenoid; the PCM needs the resistance of your model year's hardware on the new trans to function properly. Also starting in 98 the electronic pinout changed and your harness needs to be re-pinned.

Avoid the truck transmissions, there are quite a few differences (mostly with the valve body - shift load capacity springs etc.). I would say look for something from a Grand Marquis or Crown Vic (not police or taxi). The CVPI and Town Cars got a longer tailshaft and extension housing... though if you intend to swap your tailshaft anyway you could also keep your extension housing and use one of those (though again, like a Mustang trans, a police trans probably got beat on).

If you get it from a totaled car, the odds that the trans worked when the car got wrecked are high (relative to getting one from a car that has a good body - never know what put it there!).
 

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Brandon - can you explain how I would program the PCM per your note above?
You don't; that's in hardware.

Wrong impedance either it won't properly fire, or it'll burn out the drivers in the PCM.

So match the MLPS and TCC solenoid to the PCM.

RwP
 

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Depending on your tire size you might be able to get away with a 3.55 with a 21 tooth, but 3.73 is off the table unless you want to get a SpeedCal because the 23 tooth gears are known to self destruct on a semi-frequent basis.
There are alternatives to the SpeedCal; however, I have not tried this unit yet so I don't know how well it works.

UNIVERSAL SPEEDO SPEEDOMETER CORRECTOR CALIBRATOR, 1.5% to 6000%, 2-BUTTON SETUP | eBay

And my local boys, PATC, sell hardware ratio adapters ... figure out the ratio, and they sell you a mechanical adapter that does it.

Ford speedometer ratio adapter, #55RA. - PATC - TransmissionCenter.net

I'd opt for the TheWidgetMan's unit first personally; I've got his tach adapter for my 1988 Dakota, but haven't installed it yet. (Will before 1 Jan 2021 though!)

RwP
 

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Discussion Starter #11
Ah. So, when you say it's in the hardware - when I switch the MLPS and TCC solenoid, I'm good with this PCM consideration? After that, it's the OSS and re-pin then I'm good with a newer 99+ tranny right?

As always, your knowledge sharing is invaluable. thx.
 

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Yep, just make sure your transmission's MLPS and TCC solenoid are used on the trans going in (or at least parts for your model year if you want new). If you keep your OSS you can re-use your speedo gear and you'll be good up to 3.73s in the future using a 20/21 tooth gear (again, depending on tire size).

The pinout instructions in Jerry's tech article is reversed to what you actually swap - it says it's looking into the connector but it's showing the pinout of the trans side; be sure to repin the vehicle side 180 degrees out from that.
 

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Discussion Starter #15
Brandon - may have a new plan. Have the scoop on a '98 Mark VIII tranny with relatively low miles. Would this be a direct swap on my '95 Mark VIII?
 

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Discussion Starter #17
You will still need to...repin the harness. 🤔
Apologies in advance for the stupid questions. I got a 4R70W from the '98 Mark VIII (I have a '95 Mark VIII). The (newer) transmission came with the harness.

Is the re-pinning necessary ONLY if you don't have the harness that goes with the transmission?
 

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The pinout for the 98+ transmissions changed internally. You still need to change the pinout on the vehicle side to match.
 

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Look in the tech articles for Jerry's Thesis. The pinout shown is looking into the trans side connector; repin the vehicle harness to be the mirror image of that.
 
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