Rear Driveshaft Help Please!

[DKSpringer]

Hey guys-

I have a pretty significant clunk when putting the truck in gear. Getting under there, all U-joints appear tight, but I have a lot of slop in the slip splines of the rear driveshaft. Both rotational slop as well as some "alignment" slop.

First, some newbie help with the terminology. I have a NP203 and 14bolt full floating rear axle, stock to my knowledge 1977 drivetrain:
Is this considered a "2 piece driveshaft"? I mean, there are two pieces of the driveshaft connected by splines, but it's not the CV joint in the middle with a carrier bearing style.
What are the pieces of the driveshaft called? To me, a slip yoke referred to the output of the transfer case or the input of the axle, not the rear "slippy" part of the splined driveshaft.

Second, any recommendations on repair options? Is there a chance that the main part of the shaft is OK, and I only need to replace the rear "female spline" part? Should I buy a whole new driveshaft, or pull mine out and take it to a local weld shop?

I tried to grease it, but the grease just went through the zerk and out past the collar. Then, I couldn't get the collar off to inspect. Then, I ran out of time, patience, and beer in no particular order, and came to the all-powerful interwebs for help.

Thanks!