Dana 70HD - Spring Perches and Gears

[Mattman2010]

I have a 85 C30 crew cab that I am converting to a single wheel 4x4 truck. As we all know the 14b out of a k20 and the Dana 70HD out of the c30 have the spring perches at different spaces. I swapped k20 spring brackets onto the c30 frame to compensate for the difference in the spring spaces. Well now that I did that and I looked at pictures of the truck before I started to do the swap, I kinda think I want to go back to a dually, it just looks cool.

So what I am asking is, how hard would it be to move the spring perches on the Dana 70HD axle to fit the same width as the 14b? I ask this because the k20 spring hangers are a lot taller than the c30 spring hangers giving me more of the 4x4 look, and should make it about the right height to be a little taller or level with the front after I get the front converted to 4x4.

Also how hard is it to swap gears in the Dana 70HD rear end? I have a Dana 44 front axle that I plan on using till I can find a Dana 60 front end for a dually and it has 3.73 gears I want to go with 3.73 gears for more of a highway friendly gear ratio. I do not plan on towing with the truck that often, so 3.73s will still allow me to tow, but also allow me to get better gas mileage.

I also want to point out that this is the first axle swap I have ever done, and I have never moved spring perches or changed out gears before.

Thanks, Matt

[gloriavoxdei]

My D70 came with a 3.73 gear from the factory sothey are out there if you just want a new dif. As far as changing gears the D70 came in a lot of differant applications and configurations so make sure you have casting numbers and application info when you go to buy the parts. As far as the gear instal it self I've been told the D70 is basically a beefier D60 so it should be pretty straitforward.

[Mattman2010]

Thanks for the info. I have heard that you have to "stretch" the diff to get the shims out of the diff so that you can get the gears out. Im not sure if this is true or not, a guy told me this one time when I was talking to him about my truck.

[1985-GMC]

Removing the old spring perches wont be to hard, it'll just take a little time washing out the welds with a torch then some grinding.

Ive heard you have to use a case spreader on D60's so I assume the D70's are the same way.

[78customdeluxe]

Dont hold me to it, but I think you can get dually hubs for the 14bolt. I had a set around here for a while, but I sold the axle. I dont know it was a cab and chassie axle or not, I never measured the width of it though. I do have a cab and chassie axle that is a 14 bolt

[jltait]

Mattmann,
I have read on the Ck5 site that the dually and srw hubs interchange between a D70HD and 14bolt. Keep in mind though that the D70hd housing is wider than a 14bolt housing. About 67.5" WMS-WMS for a 14bolt with srw hubs and about 72" for a D70HD with DRW hubs. The DRW hubs will be 2" narrower per side vs. SRW hubs on the same axle. Check out the 14 bolt bible link

http://www.pirate4x4.com/tech/billav...ble/index.html

Good information.
JLT

[78gmc4by]

I was told that you had to use a case spreader with any dana axle when we did the gears in my dana 44 we opted to try it without a spreader it was a pain but we did it
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