Axle swap

[86chev]

How much of a pain is it to swap 3/4 ton axles into a 78 1/2 ton truck? I'd think it wouldn't be very much, if any, modification but i dont know for sure. thanks for any help

 

[crazy4offroad]

The 1/2 ton & 3/4 ton GM Corporate front axles are the same, except the 6 lug/8 lug hub assemblies and brakes, and perhaps the gear ratios. Just be sure what you have before starting, corp 10 bolt, Dana 44, Dana 60 (1 ton). The rear is pretty much a direct swap, however the rear driveshaft will be too short. The 14 bolt's pinion is shorter than the 12 bolt. Any good driveline shop can square you away there, as well as make a recommendation of whether to upgrade to 1350 yokes for the bigger u-joint. You will need the larger spring u-bolts and plates as well. Cant remember what size they are, maybe 3.25" just take the spring plate with you to a spring shop and they can fabricate you some new u-bolts.

 

[bucket]

The rear u-bolts are 3 3/8's and if you are going with lift blocks, the longer u-bolts have no trouble squeezing together enough to fit through the 1/2 ton spring plates.

On second thought, the 14FF was 3 3/8's. Not sure what the 14SF was.

 

[86chev]

its a truck i'm looking into buying possibly, the guy said it has 10 bolts front and rear and an 8in skyjacker all spring lift. seems like it could be a tough truck with some better axles under it and i didn't know how much of a headache it would be.

 

[crazy4offroad]

Driveshafts, u-bolts, and maybe a bigger master cylinder for the brakes. Wheels would be different too of course.

 

[86chev]

well i just found a dana 60 front and 14ff rear with a detroit locker for 1200 that really makes me want to do this project. however the pinion on the front axles has been rotated up. Would i still be able to make this work with 8in springs since i need the driveshafts modified already?

 

[crazy4offroad]

The rear is not such a big deal but the front can be a headache. The Dana 60 pinion is longer, which means the front driveline will need to be shortened, and also means it will be a much steeper angle, especially with 8" springs. Which is probably why it was "rotated". I would like more detail about that, like if they just shimmed it. Since the passenger side spring pad is made onto the pumpkin shims is about the only way to rotate it. Otherwise you better make damn sure you're getting a real Dana 60 before you throw your dollars down.

 

[86chev]

i will get more info and hopefully pictures as soon as possible. thanks guys

 

[86chev]

these are the pictures i got today. according to him it is a dana 60 front and 14 bolt FF rear, 4.56 gears, detroit locker in rear, open in front, the pinion on the dana 60 was roatated up, he said "it was professionally done. it was pulled apart and had a bunch of machine work done and put back together" he got the axles with a chassis he bought so he doesn't know a whole lot about the work done to the D60. he is asking $1200. whatcha guys think?

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[crazy4offroad]

Something looks very odd about that front, I would stay away from it. It's either a high pinion F*rd front D-60 that someone had the axle tubes swapped on to make it passenger drop, or it's a GM D-60 someone hacked the **** out of that passenger spring mount to turn it up like that. I'm starting to lean towards the latter, in the 2nd pic it looks like the spring plate is welded to the center section??? I dont see the 2 inboard bolts?? Either way with the pinion turned up THAT FAR the outer pinion bearing will get burnt up from lack of lube. The 14 bolt rear looks OK, just measure the spring centerbolts and make sure it is 42-1/2" before you get it. It's good to see the spring plates are there, and I would go ahead and get the rear driveshaft too. But IMO that D-60 is a piece of ****, I wouldn't give him $100 for it, IF what I think has been done to it HAS been done. This is how the spring plate is supposed to look...

 

[bucket]

Like C4 said, that front axle looks like it's been turned into scrap iron. The spring plate looks to be welded to the pumpkin, and the spring pad looks like there's not even a shim in there... it looks like the only thing there is dirt and daylight.

 

[86chev]

does the 14bolt need to be 42.5" between the centerbolts to work in the 1/2 ton?

 

[Cowboy Cadillac]

I agree with the others, the D60 looks pretty sketchy at the spring pad. If PO had the center section removed, turned and rewelded to the axle tubes, the "C"s should be sitting in the correct place(like factory) If they are not then its just a hack job upturned pinion. A few more pics of the spring pads, axle "C"s and steering mounting points would be quite helpful in a proper assesment.

 

[smurph20]

Well the Worked oover Ford D60 is a big no. THe spring pad is on the right side of the housing not the left side and we need better pics of the inner part of the mount around the spring

 

[crazy4offroad]

does the 14bolt need to be 42.5" between the centerbolts to work in the 1/2 ton?

From center to center. The other option is 40.5" which is for the 1-tons and obviously not a direct bolt-in.