[Smokngun]

Drew, YJ's don't have manual hubs like our CJ's do. They have a vaccum disconect that slides a sleve over or away from the long shaft in the front axle housing. When this system disengages, the one wheel that is still connected spins the spider gears in the open diff and the driveshaft doesn't turn. With the diff "Locked", the rotational motion can't spin the spider gears so it rotates the ring/pinion/driveshaft. Hope this explained it.

Mike H.
1983 CJ-7 Laredo,It's Orange! Now I just have to put it all back together.