Will a 3/4 ton driveshaft work in a 1/2 ton truck? 2WD I'm talking here

[turbobuick1]

Need some knowledge from you guys that have been around these trucks for a while, I'm still learning! Between a 1972 C10 and C20, and assuming that:

1) Both have the same small block and auto trans.
2) Both are 3 joint shafts.
3) Both are 2WD.

Will the driveshafts be interchangable? I'm asking because I'm doing a custom engine and trans swap into my own 1972 C20 2WD, and I will need to get a custom driveshaft made. I would like to downgrade the truck to 1/2 ton status, but I will put it off if I can, I just want to drive it!

So if I get a custom driveshaft made for my C20, and later on put in a 1/2 ton rear end, will it still work? It seems like the rear u joints for either truck have the same part number.

Anybody have any experience with this? Appreciate any help I can get!

[Ackattack]

yes and no:

I changed my 3/4 ton to a 1/2 ton. Mine had an dana 60 on it, and when I switched to the 12 bolt, it created 2 problems.

One, the rear u-joint is different size. A 67-72 1/2 ton uses a 1310 series u joint, the 3/4 tons use a 1350. You can get a hybrid u-joint and take care of that or upgrade your 1/2 ton rearend to a 1350 pinion yoke.

Second, the pinion on the 3/4 ton is longer. So when you put in the half ton rear it will slide the rear drive shaft a little further back. On mine, there was some slop, so I ended up ordering a longer drive shaft slip yoke (about 1" longer).

Good luck!

[turbobuick1]

Originally Posted by Ackattack

yes and no:

I changed my 3/4 ton to a 1/2 ton. Mine had an dana 60 on it, and when I switched to the 12 bolt, it created 2 problems.

One, the rear u-joint is different size. A 67-72 1/2 ton uses a 1310 series u joint, the 3/4 tons use a 1350. You can get a hybrid u-joint and take care of that or upgrade your 1/2 ton rearend to a 1350 pinion yoke.

Second, the pinion on the 3/4 ton is longer. So when you put in the half ton rear it will slide the rear drive shaft a little further back. On mine, there was some slop, so I ended up ordering a longer drive shaft slip yoke (about 1" longer).

Good luck!

Thank you, this information is extremely helpful! This message board rocks!