Hello, I hope you will excuse my rambling here but this is getting me down, I wish to replace my tyres and wheels but I want to do my diff first.

I wish to replace the Dana 44 rear end on my truck with another axle with say 3.55 gears. I have read the article on different axles that fit or are close and understand the spring perches on appropriate axles are 40" (although this is irrelevant I guess as my axle sits on top of the spring not underneath) centre to centre and the width overall is 60 1/2" (so 59-61" is reasonable)

I find it hard to understand things at times just reading it. I need to see a photo or drawing that shows clearly the point you measure from and to please. When the brake backing plate is fitted, do you have to guess a bit or what? People I ask are not able to explain it clearly enough for me to grasp confidently, no doubt I am just not getting it, but I hope someone can illustrate this for me.

Also, the rear ends you blokes speak of are not generally readily available here. 57-72 F100 rear ends are hard to come by or cost a bundle. People here use various axles for their cars but when I have spoken to diff shops they want to charge a bundle to build a Ford 9" tough, and I don't need anything fancy, it's a 302 and C6, maybe a 351 one day, a cruiser not a street fighter.

I just need to be positive I understand this clearly so I can go to a wreckers and hopefully find an axle to suit my width and needs, and get it modded as necessary to suit, Ford 9 inch or perhaps a Borg Warner a lot of people seem to use them on powerful cars here OK. I don't want to waste any more money on mistakes. I have spent too much now on going in the wrong direction with some things.

If anybody is still awake after all that, I look forward to your responses,

Thank you
Nev

 

I am also headed down that same path.I want to keep my stock front axle, and have disc brakes both front and rear

 

If you were to put a straight edge on the flat part of the surface where you mount the wheel, on both sides (somebody on each side holding the straight edge), you would then measure the distance between the two straight edges. That is the width of the rear. I have a 2000 Explorer with disc brakes on mine and it is 59 1/2" surface to surface. I actually used some 1 1/4 spacers because I wanted a slightly wider track to match the front. My front is a TCI MII and it wider (I can't remember the exact measurement right now).

 

Hello fellas, good to hear from you, Topmoo thanks for your comments, just let me make sure I understand clearly.

What I think you are saying is, if the 2 axles are in the housing with nothing else fitted to them, brakes etc, just the end face of the rotating axle shaft (that is the mounting point for the wheels is that correct?) sticking out of the housing a short distance, you measure from the outside face of each axle end to the same widest point on the other end.

That creates another problem, how do you measure this with the brakes and backing plate in place? Do you have to take a bit of a guess or do they not interfere with this measurement? The axle end (wheel mounting point) would protrude in front of the brakes is that correct. Just trying to think of the last time I had a wheel off.

Thanks
Nev

 

You measure it WITH the brakes and brake drum on, that is the wheel mounting surface. If the edge of the brake drum sticks out further, you can take it off, just measure the same way both old and new.

If you are going to use wheels with a different offset, you can live with a wider or narrower axle.

 

I understand that you can offset 3 or 4 inches per side . Is that right?

 

Albuq F1, thanks for your clarification to get it through my thick skull. Measure from front face of brake drum to the front face of the opposite brake drum.

Thanks fellas, I feel reasonably confident about going to chase up a certain width of diff now, all I have to do now is work out the gearing correctly if not tagged.

Please satisfy my curiosity, how much does a diff out of a 57 - 72 F100 cost in the US, or perhaps a 8.8" of the appropriate size, ideally with disc brakes?

Thanks
Nev

 

I looked at a rear end out of a 2005 Mustang , all beat up with some parts missing. they wanted $200.00 for it . Saw a 3.75 from a Exporer for $300.00 in mint

 

Hey Nev,
We used an 8.8 inch axle from a 2001 Ford Explorer with 3.73 gears - $125 at a salvage yard. They don't have to look like much - they clean up easily & do the job. This axle was a little narrow so we had to use spacers to get the wheels looking right in the fender.

Ben in Austin
1950 F1

 

I paid $100 bucks for my 8.8 with 3.73 gears and 31 spline axles, but had to purchase calipers and rotors which are readily available at autoparts stores here. Another thing to remember with the Explorer 8.8 has larger tubes, 3 1/4" so you need the perches that come with it (which you will probably have to relocate) assuming you are going to use leaf springs.

 

John, Ben and Topmoo, thanks for your further responses. Those prices sound pretty good. You would probably buy a Borg Warner for that here perhaps and people seem to be happy with them in performance cars. I had been tossing up importing a 9" or other recommended diff if I don't have any joy here.

The 8.8 " is possibly available here I will look into that.

Thanks fellas
Nev