87 Chevrolet 4x4 shift problem

[hippie667]

I am looking at 1987 Chevrolet 4x4 and it has following problem as told by owner. Does this sound serious. I have not looked at truck yet but am very interested and its not too far from me. I would like to know what possible problems this could be and if you think it would be expensive fix. I understand it would just be guess but please throw it out there so I will know what to look for. Thanks,
Ronnie

I tried to get it into 2 wheel drive put trans in neutral and shifted the transfer case to 2wd (4x4 lite went off) hubs unlocked. But would not move as if still in neutral. Tried to go to 4 hi, gears clash won't go in. Goes into 4 lo and is driveable

PS. This is automatic so I am guessing NP205?