I shift the truck Into 4wd It only drives in 4 low or neutral

Hello,

It sounds like the range fork is worn not engaging the transfer case fully. It could be a link adjustment as well. Here are diagrams and instruction to disassemble the transfer case to confirm the worn parts to fix the problem. Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.

Cheers, Ken