Sometimes these gears dont just drop right in. I think its safe to add that you can roll forward SUPER SLOW then shift the trans into neutral and then shift to desired gear on the transfer case. AGAIN SUPER SLOW like barely rolling or you can get out and rock your truck around...if you want.

 

My 96' does not move when I shift forward and to the right. Only revs engine when I hit the accelerator. All other positions work. Any ideas?

 

forward-right is low gear, unlocked. You are 'stuck in neutral'. Without somewhat regular use these things often get corroded/funky and need a little lube to get them unstuck. I'd get under the truck and spray something like WD-40 all over the top of the xfer case. The fact that the lever moved to neutral is actually a good sign.