I've bought a 96 f250 crew cab 4x4 with horriblle steering.The truck takes two hands to drive for sure.the steering is really tight and has a sticking issue at 10 and 2 the steering has to be worked back and forth to maintain a semi straight line.also the steering wheel does not return to center after turning I must steer it back to center.The PO stated that they replaced the gearbox with a bone yard box.what I have done is loosen the lash adjustment nut and turned the center shaft counter clockwise with a 3/16 Allen till it hit a hard stop,which was only about 3/4 of a turn.There seems to be very little adjustment either way tightening or loosening.the adjustment I did eased the wheel slightly but did not correct any of the problems I've described.the power steering pump reservoir seems full and its not making any noises.Iv'e jacked each side up and checked each wheel side to side and up and down,nothing seemed loose or abnormal.The truck has 305/70/16 all terrain tires.I also feel like someone has taken the steering wheel apart it makes a noise while turning that sounds like the big spring behind the steering wheel is in a bind.I would like some advice on what I need to do to fix my problems

 

Tightening down the adjuster on a worn out box will make them hard to steer and not come back to center. But it could be a lot of things. Sounds like the po threw a used steering box at it to fix it, used up all his ability to figure it out and then sold it. It isn't uncommon to have things break in the column, especially if it has tilt.
A factory service manual is something you need to invest in if you plan to work on this truck yourself.