3/4 ton axle swap for K5

[madman 72]

I have a 75 K5 with the dana 44 front and 12bolt rear. I founda 82 3/4 ton chevy that i can get the axles off of and plann to do it soon. Question being what parts do i need to get off the 82 axles drive shafts ...Should I get the tierods and steering box ? What other parts should I get off it to complete the swap. Is this a direct bolt in or will i have to modify a little. Will the drive shafts work with my existing tranny and transfercase, Granny fourspeed on K5 and the 82 NP205 on K5 and I think a 208 on 82 Should I just cut the axles to fit .if they will work.The guy said take what ever i needed. Any info will be greatly appreciated.

[Destructo]

The front and rear axle will bolt right in except for the wheel differences. You have 6 lug now and will need 8 lug, i'm not sure on the u-joints for the drive-shafts. The front axle is virtually the exact same thing you have now except for some bigger brakes and 8-lug outers, otherwise the internals are the same. The rear axle is a good bit bigger but will bolt in. The axles are pretty much the same width except I think the 14 bolt rear axles are 3" wider than your 12 bolt which will be fine, a lot of people put 1.5" wheel spacers on their 12 bolts because their narrow.

[ljbear]

The width of the rear spring perches may be different, I used axles from a 1980 and they had to be moved.

[1FaastC10]

they are a direct bolt in. jsut need the u bolts and spring plates for the 3/4 ton rear. 1 tons are the only ones with different spring perch widths out back.

[1972]

You may need a special u-joint (it is two different sizes) for the rear driveshaft to hook up to the new rear end. Most parts stores sell them. Also, use your brake calipers that are on the '75, the calipers on the '82 are different and won't work with your '75 brake hoses. Otherwise, as stated already, they are a direct bolt in as long as you have the spring plates and u-bolts for the 3/4 ton.

[Ratpowerd67]

i would take the rear spring packs also. i did this last year, i removed the rivets from my hangers and bolted them to fit 56" springs....rat

[ljbear]

Originally Posted by 1FaastC10

they are a direct bolt in. jsut need the u bolts and spring plates for the 3/4 ton rear. 1 tons are the only ones with different spring perch widths out back.

I figured the c-c on the rear spring was 40 1/2" on the 75, guess it's 42 1/2". Anyone confirm this? I don't know much about the newer trucks, except they rust faster

[madman 72]

Thanks guys all that info really helped. I didnt realize that the axles would be wider than my 12 bolt which is a big plus. Thanks again

[JIMs70GMC]

Nope they are not wider just the spacing of the spring perches could be different and the length of the rear springs could be different. The only way the rear axle could be close to the width of the front is to find a van 14BFF as they are 3" wider overall.

[Mudder]

I dont think we had to change anything on my 77 chassis when I went to 3/4 tons. Been a long time ago and I'm having a hard time remembering. Pretty much a straight swap.

[1FaastC10]

i bolted 3/4 tons into mine, no problems at all. Blazer spring perches are the same width as K10/K20 perches. i took my 10 bolt front out and replaced it with a Dana 60. still no problems there.

[Destructo]

for 73-87 all 1/2 ton and 3/4 ton truck use the same spring pad width.

[MAC67]

when we did the swap out on my brothers 85 k5 we took the 3/4 ton axles from a 75 and we had to run a special adapter u joint , it was 3/4 ton on one side and 1/2 ton on the other , little suckers were around 26 bucks apiece if i remeber right

[madman 72]

Thanks for heads up a bout the u-joints. I didn't even think about them. I am headed up to get the axles today after work and want to get started in the morning So better look for the u-joints before i go out there. That would suk to get them under the K5 then not be able to move it. thanks again guys