Alright, After driving in four wheel drive, the front end will start to lock up and the truck gets stuck in 4wd. After the truck cools down, I can roll forward a bit and the 4wd will disengage. I figured before maybe the transfer case was empty, finally got the fill plug open (had to drill it) and there is oil in there. Any other ideas why this is happening? The truck is an '87 Pickup with a 22r carb.