It appears when i put the truck in 4 wheel drive it does not actually go into 4 wheel. It has lock outs and have made sure I put them in 4x4… why would it not go into 4 wheel, as there are no vacuum lines or solenoids (electric).
Sounds like you need a good independent mechanic to check things out. Lockout hubs work in several different ways so I would be guessing at any solution since the truck is 40 years old.
You’ll need it to be hoisted up on a shop vehicle hoist to test the system .
Engine running and transmission in gear, put the 4x4 through its paces to see what IS and what is not turning. you’ll be able to tell if the transfer case is spinning the drive shaft and if the front axle is spinning the wheels.
Only up on a rack can you tell where the weak link is.
shift linkage ?
Transfer case ?
Locking hubs ? ( maybe even just one )
what if i try to move the truck in 4 low with the rear end up in the air, just to see if it pulls?
@grego2: I guess that would work, but aren’t you risking knocking it off the jack or stands and causing more damage? You’d be better off putting it on a lift.
Edit: That actually sounds pretty dangerous to me. Just take it to a good indie mechanic. They’ll put it on the rack, and test it for you. Will only take a few minutes, and they’ll probably be able to figure out the problem pretty quickly if the wheels don’t spin.
This what I would do I would jack up the front end. Put jack stands under the axel. Do Not start the truck. Put transfer case in 4 high. Make sure lock outs are in 4x4 lock. Then see if you can turn the tires by hand. The drive shaft should not turn. But it should try to. If it turns then your problem is in the transfer case. My bet is problem is in the lock outs.