Well, after many exhausting days sitting in the back yard, tearing the old girl apart, I finally got the front dif carrier out and emptied. As I suspected, the ring and pinion were fine, but he spider gears and casing were all $!@$^#&@$@. Out of the 4 gears, one was completely cleaned

One had 1 tooth remaing

and the other two wore the same grins as those characters from Deliverance.
All the splines and bearings appeared fine, as were all the seals and sort. So, I gutted the front dif, and replaced it back in the truck. I'm now strictly a 2WD but at least I have some wheels to get back and forth to class in.
I have good mind to shoot some photos and a nasty gram to Toyota Motor Corp. to show the failure of these parts and demand something be done about it. I couldn't believe my eyes!
Anyone have any good contacts on how to go about this?