9 Silverado 2500 Steering sticks, why?

I just picked up another farm truck last summer and like many old Chevy's it came with the infamous chevy loose steering wheel adjuster knuckle. I took it apart and tightened the two screws you can get to without major surgery. Ok that worked but I noticed that it seemed to have a slight hitch in the steering when you turn the wheel either direction more than around 60 degrees. I first noticed it after I fixed the loose wheel knuckle but it could have been there before as it sort of flopped all around at that point. I took the wheel off again and made sure nothing is rubbing as a result of my messing around in there behind the lock plate but found nothing.
The sticking seems to be like a the way a trucks wheels sort of hump when you crank the wheel all the way around full to the locks. The wheel always turns fine and since I have had it 4 months it hasn't gotten any worse or better. The truck has 142 K miles. It seems to me like the power steering may be going though I never had one go before so I can't judge it well. Yes it has plenty of fluid and the serpentine belt is tight and working fine. The truck does it the same way at any speed fast or slow about the same way.:sly: Ah well, not much to hollar about for a $550 4 wheel drive

Whoops, forgot to proof read the title, the truck is a 1990