JonxSmith

This is no urgent issue or anything.. Just had a few questions..
With that being said, heres the deal.
Recently I picked up a running 74 k10 for $400.. Truck was barely running, tuned it up, and its running like a champ.. I have a few problems though..
My foremost concern is that, the forward gears seem to work flawlessly, transmission was rebuilt less than 10k miles ago, and when put into reverse, it hesitates for about 3 seconds, and grinds (or thats what it sounds like) and falls into reverse.. Is this a serious issue I should look into?
And secondly.. The viser on the truck (all original) says it was full time 4x4, and from what I've read, forgive me if I'm wrong.. But I've read that means it has an np (new process) 203 transfer case.. When on the road in high lock, it chirps the rear right tire, as if its a posi.. But today, I put it in 4wd to pull a tree out of my yard, I put it in low loc, and when I went to pull, only the front and rear right tires pulled.. It was my understanding when in lock all 4 front and rear were 50/50 power ratio in this truck.. Is something wrong, or have I read some mis-information?
Any help would be appreciated. Thanks in advance,
Jon