axle swap

[zombeats13]

I have 1976 GMC sierra classic 4x4 and I have heard that switching from 1/2 ton axles to 3/4 ton axles will give me the gear ratio to run 35" tires for cheaper then regearing the stock axles I have on my truck. Would axles off a 3/4 ton truck of the same year bolt on to my truck's mounting points or would I have to do som e custom work? I have a 6" lift all leaf springs. I don't know if makes a difference it is a short bed.
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[ghettoluxury]

1/2 and 3/4ton are the same all the way around and 1 ton are the same up front. To run 35's you are going to want to look for 4.10 gear ratio.

[84SierraClassic]

Just for reference I have 35s on my truck, stock 1/2 ton axle...sorry don't know the ratio right now I just got it. It performs alright, granted I don't drive on the road with it either. It spins through the mud real well though.

[russgt]

Your 76 has a dana 44 front and a 12 bolt rear axle. Standard ratio was most likely a 3.08 with a 3.42, 3.73, and possibly a 4.10 being optional. Upgrading to 3/4 ton axles Will get you either a dana 44/corporate 10 bolt front axle and a 14 bolt rear axle. Standard ratio should be 3.73 with 4.10 and 4.56 being optional. 1 tons use a dana 60 front axle with a 14 bolt rear.

With 35's, look for 4.10s or 4.56s.
3/4 tons will bolt right in. There are some minor changes to make to run a dana 60. The spring perches on the 1 ton 14 bolt are set up a little narrower than the perches on the 1/2 and 3/4 axles. Dont forget that the 3/4 and 1 tons are 8 bolt wheels.