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Swapping for 3/4 tons?

N

nau81blazer

1/2 ton status
Joined
Mar 6, 2004
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Location
Cincinnati, OH
Hey all,

I know many of you have done this so I was wonder if you could help me. I might be getting ahold of some 3/4 running gear and was wonder what modifications would need to be made. I believe that they are out of a 74' k20. I'm going to be putting them into an 81' k5. Will the spring plates need to be moved? Will my steering bolt up to the new axle? Any modifications need to be made to brakes? Thanks for any input you can throw my way! :bow: :bow: :bow:

--Adam
 
The front axle is plug and play with the exception of the calipers, those will have a 7/16" banjo bolt instead of your 10mm banjo bolt so my suggestion is to unbolt your calipers and swing them out of the way and once the donor axle is swapped in bolt your calipers to it. The rear axle will be plug and play as well with the exception of the e-brake cables will be different but depending on the style of cables it has you might be able to use your existing ones over. The spring perches and shock mounts will all be correct but you will need the top plates and also a conversion u-joint.
 
I thought also new ubolts for the 14 bolt :D . I am getting ready to do the swap soon as well. :eek1:
 
I would have hoped that would be a given but i was thinking i should have put that in there also. It would be someones luck to think they had everything needed for a weekend swap and once everything was out and the new stuff ready to install and all the 4x4 shops closed then they would find out they need new u-bolts as well.
 
new ubolts all the way around is a pretty good idea. be sure to buy plenty of gear oil, brake fluid.

be sure you inspect the brakes.
 
awesome!! Thanks for all the info guys!! The axles are in an existing vehicle so I'll make sure to get the u-bolts from him. The coversion joint can be purchased at NAPA right? thanks,

-Adam
 
Anybody have that NAPA part # handy for the conversion U-joint? Also, I though I read somewhere that the rear driveshaft has to be shortened due to the 14 bolt diff being larger (pushing the yoke farther forward than a 10 bolt's)? As soon as I get my 14 bolt back from the rebuild/Detroit install, I'll be tackling this same project.
 
i lost the part number, and im sure someone else on here will give it up, but in case not, just got o NAPA and look at 2 u-joints from the 14bff and the 10b and measure the endcaps, then they'll have a little book they match them up with to find the right part #. well i know the driveshaft will not have to be replaced if you have an np208 (slip-yoke) t-case. otherwise im not too sure.
 
Just for reference , there are TWO np208 slip yoke driveshafts . One in 1310 with internal clips for the 81-82 trucks with 12 bolts , and one in s44/3r for some 82 and all 83 up trucks with 10 bolts .

Either will fit the np208 , but each requires a different conversion joint to the 14bff 1350 .

This threads starter just bought a 10 bolt shaft from me for a np208 and informed me he had internal clips on a 12 bolt , I said what year , he said 81 with stock 12 bolt . So he needs a conversion joint for even his 12 bolt .
 
pauly383 said:
Just for reference , there are TWO np208 slip yoke driveshafts . One in 1310 with internal clips for the 81-82 trucks with 12 bolts , and one in s44/3r for some 82 and all 83 up trucks with 10 bolts .

Either will fit the np208 , but each requires a different conversion joint to the 14bff 1350 .

This threads starter just bought a 10 bolt shaft from me for a np208 and informed me he had internal clips on a 12 bolt , I said what year , he said 81 with stock 12 bolt . So he needs a conversion joint for even his 12 bolt .
Click to expand...

10 bolts have 1330 U joints
12 bolts have 1310 U joints :D
 
10 bolts have s44/3r . Search button proves this , even though a well regarded member or two bought a truck with an aftermarket 1330 30 spline yoke :thumb:
 
for the 10-bolt it is Napa part # 240-0358. (1330-1350) I apparently have the s44/3r and not the 1330.
According to Four Wheeler Jun '04...1330 has 1 1/16" bearing cap diameter and the 1350 has 1 3/16" bearing cap diameter. It turns out the s44/3r has 1 1/8" diameter. Back to Napa I go.:doah:
 
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