So I've owned my F250 for about 6yrs and it's been in the family for about 15+ yrs.
I've allways had aspirations to make her a dually. So finally I found a donor and over the weekend I swapped out the box on it and switched the wheels on it. Well the inner wheels rub the Leaf springs which I hadn't anticipated.
So I measured both axles and the one on my truck is 57" and the one on the donor is 61".
I'd swap out the axle but I'm affraid in doing so that my truck won't shift correctly!
My f250 has a C9 rear and the f350 has the D5 rear

Now my question is will I be better off buying spacers and longer lug studs or am I over thinking it and should I just throw the D5 in and call it a day?

Any help would be greatly appreciated!!
Thanks

 

Welcome to the site.

Better to put the right axle under it. I'm not a big fan of spacers, especially if you plan on putting weight on it.

What are the ratios?

 

Thanks for the welcome! Glad to be here

Yea I'm thinking thats what I wanna to but I wanna be sure before I do it that it will shift properly.
I believe the C9 has 3.55 gears and the d5 has 4.10

 

What year truck? Not sure how much affect it will have. Just throw off the speedo, slow you down some. Adds some power. Depending on year, you can get tuners to adapt shifting and speedo.

 

My truck is a 93 f250 xlt the donor is a 87 f350
I don't care if the speedo reads correctly I mean off a little would be ok I just don't wanna have improper or irratic shifting. I appreciate all the help I knew ford guys would be helpful.
I love my truck and want to cut no corners when redoing her everyone keeps saying spacers but I can't help but think that would be a weak link and I don't want that.

 

Lots of people use spacers anymore getting strange wheels to fit their application. Personally I won't.

Do it right.

 

welcome to FTE.
i would swap the dually rear into your truck.
the 4.10 gears will give you much more pulling power and off the line grunt.
the slight difference in fuel mileage will not be that big of a factor for in town stop and go driving, and may even be better with the 4.10's.

out on the road you will probably see a 2 mpg or so drop on straight highway driving.

 

If it's 4x4, wouldn't you have to also change the front differential to 4.10?

 

Your '93 has the electronic speedo, which gets it's signal from the VSS on the rear axle. The 87 axle probably doesn't have provision for a VSS...

 

Thanks glad to be here

I Want to swap the 4:10 in i could careless about the mpg loss my only concern is about the VSS and the truck not shifting correctly

It's 2wd

Your thinking what I'm thinking lol it does have a VSS on the axle but I'm still concerned about shifting properly. The 93 f350's came with the same D5 4:10 posi trac that's in the 87 Just unsure of they have a different type of VSS anyone have concrete evidence that they would?


I truly do appreciate all the help guys and I hope with knowledge I gain through this process I can help someone down the road

 

All the VSS does is count the teeth of the tone ring as they pass by the magnetic sensor. Where that signal goes from there is a function of the truck's wiring and would have nothing to do with the axle. If there is any difference it will be in the tone ring, not the sensor or the axle.

So pull the covers off both and look at the tone rings. If the teeth are of the same size and spacing you won't have any problems.

The '93 has a four speed automatic with overdrive, right?

 

Yes 4speed automatic with overdrive

I Will have to check that then! I had a problem before where I had irratic shifting due to a bad VSS so that's what frighten me when I realized my axle was too short and I'd have to use the D5 otherwise I probably would have cluelessly jumped into swapping axles thinking everything would workout. Again thanks for the knowledge

 

I think your donor truck is a Chassis Cab, thats why it rubs your springs

 

no, the tires are rubbing the springs because he tried putting dual wheels on a single wheel rear. the dually pickup rear is wider than the SRW pickup rear to compensate for the dual wheel rims.

a cab chassis rear will not fit under a pickup because the cab chassis frame/ spring perches are 33 inches wide, compared to the pickups 36 inch frame/spring perches

 

point taken but why is there 4 inches if difference in the overall measurement? They Made Chassis cab SRW's in 87-97. so the wider measurement is an error? Im just not understanding the 4 inch difference. as far as the true dually vs Chassis cab axle width, having owned both I know about. I was meaning maybe there is a difference in axles between a regular 250 vs a Chassis cab srw 350