I'm swapping a 95 7.3 and E4OD into an early model truck. That said, the donor engine and trans I bought do not have complete wiring harness' or computer, they came from a '95 E350.

[1] What year[s] wiring harness and computer will work with this engine/trans?

I already know I will have to buy an aftermarket shift controller because I am not using the E350 rear end.

[2] Is the instrument cluster needed for any engine or trans control?

Thanks in advance!

 

A wiring harness, computer, IDM, etc from any automatic 95-97 PSD will work.
The VSS in the E350's rear axle sends a signal to the PSOM that controls the speedo and odo, the PSOM sends a modified signal to the PCM so that it can know when to shift gears. I think you will need the PSOM and at least the center section of the dash that has the speedo and odo.


I've thought about how to get around the VSS before when using a different rear axle. My idea was to laser cut or water jet a plate that mimicked the teeth that the piece that the VSS reads. This custom plate would need to be mounted to the drive shaft or transmission output shaft. A bracket would need to be fabbed up to hold the VSS in the correct position. The size and number of teeth would need to be adjusted for the gear ratio of the rear axle to compensate for the difference in rotational speed between the drive shaft (or transmission output shaft) and the axle shaft. If you want to go this route, I'd be happy to help figure it all out for you. This method would save you from buying an aftermarket controller.

 

So if using a 2 speed rear, I would need two gears and the ability to shift the position of the VSS to the correct gear, right?

Also, the gear would have to be bolted to the pinion flange so that the changes in driveshaft angle do not change the distance between the gear and the VSS?

Also, I am a newbie to the Powerstroke and the acronyms for it's modules, sensors and controllers... could you translate? Lol!

Thanks!

 

Yes. But remember, this is just an idea I dreamed up a while ago. It is untested, but I am willing to help work out the details if you are willing also.


Couldn't it be mounted to the transmission output with the sensor bracket off the transmission as well?


VSS= Vehicle Speed Sensor [it is a non-contact sensor]
PSOM= Programmable Speedometer Odometer Module (I think that's what this stands for)


EDIT: IDM = Injector Driver Module

 

I'm sure it could be, it's really too bad it isnt from the factory!

I'm currently looking for a 2 speed diff that will work. The lower of the two ratios would have to be 7.17:1 so as to match the front diff. I have looked for matching diffs for front and rear in higher ratios but they are simply not available without swapping out the entire assemblies to Rockwell or such. I'm simply not going to spend that kind of money.

 

I think this is a really cool idea, just did some looking, those C series trucks are cool! Subscribed.

I don't know much about 2 speed rear ends, so please discount/forgive if its off base, but wouldn't the output speed of the drive shaft be the same no matter what the rear end was doing?

 

Yes, and that is why there would have to be two rings so the trans would shift at a lower speed. The lower the ratio, the more teeth on the ring.

I too have always like the C series and am completely nutz about the stance and ride height of this old fire truck!

 

Ok that make sense. I learned something today! And yes, that stance! I saw your thread in the other section, the fact yours is 4wd makes it cooler yet!

 

The stock setup, the VSS reads the tone ring on the RING gear, so it's basically reading the speed of the axle. If you're able to replicate that, it wouldn't matter if the diff were a two-speed, or what ratios it was, or what tranny or transfer case or whatever was upstream. By measuring axle rotation, as long as it's calibrated to the tire size, it's going to report the correct speed regardless of the gearing.

 

TONE RING, that's the word I was looking for!
I don't think it will be possible to make a tone ring for the axle shaft, so that means taking a reading upstream of the differential.

 

Exactly, so the number of teeth on the trans mounted tone ring would be reduced by 7.17 times based on my current ratio.

 

^^^^ But even a two-speed diff has a single ring gear, which more or less turns at the speed of the rear axle, no? I've never seen one on the inside.

 

You are right, but since the reading will be taken from the other side of the pinion, which does change, there would be a need for two tone rings.

 

Tire size is 44" diameter.

 

Is the VSS magnetic?