Engine/Transmission (1994 - 1998) Are the Ford & Dodge 271 t-cases different?

[SRath]

I know it's probably a long shot, but I have an opportunity to buy a 271 t-case for what seems to be a reasonable price. It is from a Ford, however, and I'm wondering if anyone knows if it will fit or if it could be made to fit my Dodge (with an NV5600) without tremendous expense?

 

[tony597fitter]

I think (dont quote me on this) I read awhile back they will bolt up. You have to check the input shaft splines. They come in 24,31 and 34.

 

[Lightman]

A NV5600 runs a 29 spline output and no ford runs a 29 spline input.

 

[SRath]

So it is the input splines that nixes it? I wonder how expensive it would be to change that? I'll call a local transmission shop tomorrow.



Thanks for the input, guys! You know how these deals are; move quickly or miss out; but move too quickly and waste your money.

 

[tony597fitter]

I know that you can put a 271 in a dodge. There are guys on comp. diesel doing it.

 

[SRath]

It would be great to also swap a 271 for my 241DLD when I do the NV5600 conversion I'm committed to and close to doing since I am already going to be paying for driveshaft shortening & lengthening. But there is one major issue I need to resolve first. That is the speedometer, which gets it's signal from the t-case in my '96.



They quit putting the sender in the t-case in '98(?), I believe, and moved it to the rearend. I may be wrong on the year it changed, and someone please correct me, but whatever year it was, even the older 241DHD's that have it are hard to find. No 271 has a speedo sender apparently. Besides, if you're going to upgrade from a 241DLD, why not get the much stronger 271 instead of the "little bit" stronger 241DHD?



If I could resolve the speedo issue, the 271 would definitely be my upgrade of choice.



I see two possible ways to do that: One would be to find a later model rearend with the speedo sender and swap rearends, too. No getting around the high expense of that idea, though. And there's no guarantee the speedo in my truck could even use the signal from a later model rearend.



The other possibility, that I can't seem to get a definitive answer either way about, is to use a signal convertor box from Dakota Digital that might allow me to use the antilock brake signal off my '96's current rearend and convert it to the proper signal for my speedo. It's called the model SGI-5 Universal Speedometer Signal Interface.



If I understand it correctly, it simply takes the "pulses per mile" from any tone-ring type sender and converts them to a different number of "pulses per mile". There's probably more to it, but that's the extent of my comprehension. I think it is intended to compensate for tire and gearing changes as well as some driveline swaps.



If that would work, the cost of the little black box is under $100 and makes a 271 swap seem much more worthwhile and affordable. I contacted Dakota Digital and asked them about doing that (taking the antilock brake signal from my current rearend, which appears to use a carrier-mounted tone-ring sender, and converting it for use with my speedo using the SGI-5), and they think it might work...



I have no idea if it would interfere with or eliminate my antilock rear brakes, though. I don't see why it should as long as the brake module still receives a signal, too. I would just be tapping into it, not rerouting it.



If anyone reading this has a more definitive answer, I would sure love to hear it.



Otherwise, I'm working up the courage to simply gamble on the cost of the SGI-5 and try it right now by just bypassing my t-case sender and tapping into that brake signal. It would either be an economical and simple solution, or an expensive education...

 

[tlgdiesel]

It would be great to also swap a 271 for my 241DLD when I do the NV5600 conversion I'm committed to and close to doing since I am already going to be paying for driveshaft shortening & lengthening. But there is one major issue I need to resolve first. That is the speedometer, which gets it's signal from the t-case in my '96.



They quit putting the sender in the t-case in '98(?), I believe, and moved it to the rearend. I may be wrong on the year it changed, and someone please correct me, but whatever year it was, even the older 241DHD's that have it are hard to find. No 271 has a speedo sender apparently. Besides, if you're going to upgrade from a 241DLD, why not get the much stronger 271 instead of the "little bit" stronger 241DHD?



If I could resolve the speedo issue, the 271 would definitely be my upgrade of choice.



I see two possible ways to do that: One would be to find a later model rearend with the speedo sender and swap rearends, too. No getting around the high expense of that idea, though. And there's no guarantee the speedo in my truck could even use the signal from a later model rearend.



The other possibility, that I can't seem to get a definitive answer either way about, is to use a signal convertor box from Dakota Digital that might allow me to use the antilock brake signal off my '96's current rearend and convert it to the proper signal for my speedo. It's called the model SGI-5 Universal Speedometer Signal Interface.



If I understand it correctly, it simply takes the "pulses per mile" from any tone-ring type sender and converts them to a different number of "pulses per mile". There's probably more to it, but that's the extent of my comprehension. I think it is intended to compensate for tire and gearing changes as well as some driveline swaps.



If that would work, the cost of the little black box is under $100 and makes a 271 swap seem much more worthwhile and affordable. I contacted Dakota Digital and asked them about doing that (taking the antilock brake signal from my current rearend, which appears to use a carrier-mounted tone-ring sender, and converting it for use with my speedo using the SGI-5), and they think it might work...



I have no idea if it would interfere with or eliminate my antilock rear brakes, though. I don't see why it should as long as the brake module still receives a signal, too. I would just be tapping into it, not rerouting it.



If anyone reading this has a more definitive answer, I would sure love to hear it.



Otherwise, I'm working up the courage to simply gamble on the cost of the SGI-5 and try it right now by just bypassing my t-case sender and tapping into that brake signal. It would either be an economical and simple solution, or an expensive education...

Changing to a newer rear end would not change anything the newer rear ends run the same pulses per mile as the older rear ends. Which is still not what the speedo in the older trucks require. As far as the dakota digital box I cant answer that. I am using that box in a little different situation. I am running a ford np205 with a 2000 ppm signal generator and modifying the signal off of that with the SGI 5 to a 4000 ppm signal.

 

[SRath]

"And there's no guarantee the speedo in my truck could even use the signal from a later model rearend. "



"Changing to a newer rear end would not change anything the newer rear ends run the same pulses per mile as the older rear ends. Which is still not what the speedo in the older trucks require. "



Just what I was I was afraid of... But there may be some good news here: Are you saying that Dodge did not change anything as far senders on the rear axle? They just did what I am wanting to do and shared that rear axle signal with both the antilock brake module and the speedo? So my current axle sender is just the same as any late-model's?



In order to use the ppm signal from the same old rearend sender, they must have changed the receiving unit for the speedo? If so, that is exactly what the SGI-5 is supposed to compensate for, isn't it? Mismatched ppm senders/receivers. That little SGI-5 might do the job after all, don't you think?



But hold the phone! You have the legendary, cast iron, gear drive NP205 in your '96 Ram?! I would take that over a 271 any day, and would love to hear the details. Is it a divorced setup or direct mount? I see you have an automatic, and I have an NV4500 right now, but an NV5600 is sitting in my shop waiting for installation. Does that change things, or can an NP205 still be installed?



I had a Chevy with a 454 and NP205 I wanted to put an NV4500 in and looked into it. I found a transmission shop that said my spare NP205 for a TH400 (new round-style adapter flange) was exactly what was needed along with a Dodge output shaft in the Chevy NV4500, and that it was very feasible to do the swap. So I knew the Dodge/Chevy NV4500 transmission in front of an NP205 can be done. However, the Chevy NP205 has the front axle drop on the passenger side and therefore that particular setup will not go into the Ram pickup.



It's too bad the front axle drop is different (Ford-style) on the Ram, I have Chevy 205's for every Chevy pickup transmission squirreled away in my shed already. I know nothing about Fords (sometimes ignorance really is bliss! ). Other than a divorced setup, I didn't know a 205 could be adapted to our Dodges.



More info please?

 

[SRath]

Hello? tgldiesel...?

tlgdiesel : "Changing to a newer rear end would not change anything the newer rear ends run the same pulses per mile as the older rear ends. Which is still not what the speedo in the older trucks require. As far as the dakota digital box I cant answer that. I am using that box in a little different situation. I am running a ford np205 with a 2000 ppm signal generator and modifying the signal off of that with the SGI 5 to a 4000 ppm signal. "



*********************************************************



tlgdiesel, Did the Ford NP205 you are using come with that 2000 ppm signal generator, or did you add one somehow? If so, how?



None of the GM NP205's I have are equipped with signal generators; just cable speedo drives.



Does my '96 require 4000 ppm? Your post seems to indicate it might be different?



I am going to try doing the NP205 conversion along with the NV5600 in my '96. I used your advice to track down all of the needed adapters and I found a Ford NP205 t-case. Now I really just need to get the speedo solution worked out.



You seem to be the only one with information on using the SGI-5, or anything else, to fix the speedo problem, but you aren't set up to receive pm's.



Hopefully you'll see this post, and can I contact you somehow?



Thanks!

 

[SRath]

Hold the phone!



I think I just figured it out! You said you had a 2000 ppm signal generator. That got me wondering... "signal generator". . hmmm... So I started searching the 'net for "speedometer signal generator"...



Turns out there are MANY such signal generators available that simply screw into the cable drive on a transmission or t-case and convert the mechanical drive to an electronic square wave signal. Just what the doctor ordered!



Together with the SGI-5 to convert their ppm signal to whatever ppm my '96 Dodge speedo wants, this looks like it will be easy to do, and not very expensive, either! It is definitely easier than using a later model NP241DHD t-case with neither a ppm signal or mechanical speedo drive.



I would still like to talk to you, tgldiesel, about some of the other details of the NP205 conversion you did.