The front of the prop shaft has a longer cv boot that has forward and backward flex as well as side to side:
The part that connects to the transfer case looks like this:
This is the part that is bad on mine. I opened it up last night an its dry as a bone inside.
My theory is that this is the end closest to the ENGINE therfore gets the most force - its prolly getting TWEAKED by the tcase when the energy hits the driveline.
Its 75 bucks for this so I went ahead and ordered one. My front seems fine, but if i have more problems I might shell out the $400 for a nice double u joint.
Also, if you on a SUPER budget - it looks like after prying the top off the gold cover, you could pack it full of grease and hope you get another 10K out of it.... IMHO.