chevy dana44 axle swap questions and general axle swap questions

[malodin]

Ok, so i swapped in a chevy d44, it bolted right in and looks even and all. but i was taking some measurements.

ball joint stud to ball joint stud on the jeep is 51.5
ball joint stud to ball joint stud on the chevy is 54.5

thats a net of 3" wider.

so i measured the long tube of the jeep and chevy

chevy is 1" longer than the jeep.

short side is 3" longer than the jeep for a total of 4" longer than the jeep yet i only got 3" total.

i dont understand how this is becuause if the chevy is 3" wider on the short side and 1" wider on the long side and the spring purches are in the same spot as the jeep i should have gotten 4" width difference.

on top of that, ive been reading up on narrowing tubes and what not for my rocky project.

If i want to stay with the spring under the frame and not outboard it what would i have to do? just measure the distance from the housing spring purch to the inner C and make the same on the long side?

[baja]

The ball joint measurement is probably a little more accurate.
The differences in the tube measurements are due to the different castings used for the "pumpkin" and the the placement of the spring pad in relation to the center of the differential and the amount of material in the casting around where the spring pad is.
Another good way to tell the difference in width is measuring the axle shafts of both axles.
But overall, I would say the 3" difference at the ball joint is correct, I believe a wide track FSJ 1/2 ton/cherokee front is 64" and a chevy 1/2 ton front is 67".
baja

[malodin]

thanks baja, this is chevy 3/4 8 lug. so basically no 2 dana44 housings were built the same?

[malodin]

ok i got another one for you, i have a hpd44 i want to turn into a passenger drop axle. ive been doing the reading and am prety confident that the tools i have between myself and my work and my fathers work i could do the actuall swapping pretty easily. my questions come into play when figuring out how wide i want to go and stuff.

The d44 i have has no provision for leaf spring purches on the housing its self(now this might seem good because i can weld a spring purch right up against the housing) whats the reason they put the pumkin all the way under the leaf spring or over it depending upon chevy/jeep?

It seems to me that if i were to put the leaf spring purch right next to the pumpking yes the u-joint input might be a little further away from the leaf spring, but at the same time that might make it line up with a d300 case easier.

I was doing some measurements on my th400/d300 swap and its like 8" center of ujoint to frame and the pumpkin is like 6" center to ujoint to leaf spring(which is the same distance as the frame)

Final question supose i just put a leaf spring purch on the tube right next to the pumpkin on the short side, then would i measure the distance from the leafspring to the inner C and make it the same on the other side? it seems like thats what i would have to do other wise the whole axle would actually be off set

[baja]

You've got a couple of things to keep in-mind while doing what you are talking about.

1. spring mounting width, the distance your springs are apart, center to center. On our FSJ's waggy's and 74 and later vehicles I think it's 32".
2. over-all axle width. what ever measurement you use, like ball joint to ball joint or wms to wms or what ever, keep it consistant. Always use the same measurement references.

You want the spring mounting distance centered on the axle in relation to your over-all width.

Everything you do/measure should be based off of working from the center of your vehicle.

As for where the pinion measures to, again go off of center left to right. Where it ends up beingin relation to your transfercase output and the center of the axle is important. The final location will depend on the length of the axle shafts that you are using and where you can place the the spring perch on the housing. The closer to the center of the axle you get, the more drive shaft to transmission, bell housing and starter clearance becomes an issue. The farther off center it is, the more your spring perch placement becomes an issue because of the differential housing and having a place for u-bolts etc.

As for axle shafts, of Dana 44 front ends, between GM, Ford, Dodge, IH and FSJ's. They all used different combinations of lengths of inner shafts.
Do some measuring of all the shafts you can find or get your hands on. In order to get the over all axle width you want with the pinion placement you need you may need to put a combination of parts together that were never offered from an OEM.

But most of all, MEASURE EVERYTHING. Many times before you cut or weld anything. Also keep in mind you may have to redo it a couple of times to get it right, but the better you measure and prepare the better chance you have getting it right the first time. And take lots of pictures and keep us posted on the progress.

Good Luck,
baja

[malodin]

baja, thank you that helps out greatly. I do have one question on

"The closer to the center of the axle you get, the more drive shaft to transmission, bell housing and starter clearance becomes an issue. The farther off center it is, the more your spring perch placement becomes an issue because of the differential housing and having a place for u-bolts etc."

are you saying that the closer the spring purch gets to the axle(i.e. grinding the housing down so it sits on the spring) will be more difficult than if i were to leave the pumpkin closer to the center? or visa versa?

[baja]

baja, thank you that helps out greatly. I do have one question on

"The closer to the center of the axle you get, the more drive shaft to transmission, bell housing and starter clearance becomes an issue. The farther off center it is, the more your spring perch placement becomes an issue because of the differential housing and having a place for u-bolts etc."

are you saying that the closer the spring purch gets to the axle(i.e. grinding the housing down so it sits on the spring) will be more difficult than if i were to leave the pumpkin closer to the center? or visa versa?

Basically it's like this, if you have the spring perch completely away from the differential housing casting, (placing the pinion towards the center of your axle, left/right) the spring perch could simply be welded to the axle tube and your u-bolts would simply go around the axle tube, much like on a rear axle or the non-pumpkin side. But if you do it this way, you may have drive shaft clearance issues around the transmission and engine areas. Now if you go the other way with the pinion (away from center of axle) you have the differential housing casting to deal with. You are talking about using an axle housing that has no spring perch formed into it where you will need one. When the OEM's cast in a spring perch on the housing they add material as nescessary to get a good spring perch and cast in special features to make room for the u-bolts, sometimes even they don't have room for two u-bolts and instead they use one u-bolt and a couple of studs into the housing. (chevy and dodge dana 60's and dodge dana 44's) But they have the advantage of being able to have the casting made the way they need it. You don't, you'll have to figure out which axle shaft combination works best to get you your best pinion location and still get a good spring perch on your housing to end up with the width you want while keeping everything centered. Do lots of measuring and calculating...
baja

[malodin]

Baja, this is exactly the kind of info i am looking for, very much appreciated. for now i will probably slap in a chevy d44 so i can roll it, and setup my engine/tranny/tcase then once that is in i can figure out how i need to setup the hpd44

[malodin]

looking at this picture, it shows a spring mount on the outside of the housing, on both sides, yet the drive shaft is pretty well inline with it, given this i think i could move my hpd44 over to that side relatively easy, use those purches right up against the diff housing, then make the axle stick past the leaves however far which ever short side will match the axle sticking out the long side's axle(so they are even)