203 output yoke size

[77 K20]

So I've been trying to find a replacement rear driveshaft for my truck. Right now I have a 1350 u joint at the differential but only have a 1310 u joint at the back of the transfer case.

One driveline shop said on a 3/4 ton both u joints should be the same size.

Did someone maybe swap out the 203 with a 1/2 ton before I owned it? And the 1/2 ton has a smaller u joint at the yoke?

Or they said replace the yoke out of the 203 with a flange where a 1350 CV could bolt up. How easy is that to do? Can that be done with the transfer case in the truck, or does the whole thing need to be dropped?

 

[crazy4offroad]

1/2 ton is 1310 so the tcase likely got swapped. The yoke is easy to swap whether slip yoke or bolt-on, just might have to borrow the right socket for it if you don't have any above 1".

 

[77 K20]

Thank you! Thank you! Thank you! I thought it might be the case, but had no way to verify it. Now I know what to do.

The front driveshaft between the 1/2 ton and 3/4 ton were the same, right?

I'll be ordering my rear driveshaft tomorrow. I want to get everything done before hunting season/winter.


So to swap out the yoke there is just a big nut to take off and it slides out? No need to remove the tail shaft section?

 

[crazy4offroad]

Fronts are pretty much the same. I think 76 has a fixed yoke, not sure if 77 or 78 was the year break for the double cardan joint. The rear yoke is either bolt-on or slip-yoke depending on your application. If yours is bolt-on put a little silicone on the splines before assembly otherwise you may have a little gear oil weeping past the splines.

 

[firebane]

If your going to do the yokes get the seals as well ESPECIALLY on a 203. Would hate to see all that work then up with a leaky or seepy transfer case.

 

[77 K20]

Thanks for all the info. I just ordered a new 1350CV driveshaft, yoke, hardware, and seals from Tom Wood's driveshafts online. The local place here couldn't be bothered to answer any of my questions or even look at the truck.