New to me 2001TJ SE manual 5 speed. Drives fine in 2WD. Was out today with a friend and could not get it to shift to 4H or 4L. By that I mean the shift handle wouldn’t budge at all. I disconnected the linkage and then the handle moved freely. I hit all the joints for the linkages underneath and beside the transfer case with lube. Let them sit, hooked it back up and it still stuck. Tried it in gear, in neutral, rolling slowly forward and reverse… nothing. Is it possible the linkage that directly attaches to the transfer case is frozen up? Should I try a gentle tap with a rubber mallet? If it was functioning properly should I be able to switch it by hand from underneath if all other linkages are disconnected? Any advice is very much welcomed!