The tjs and later xjs never used a vacuum setup on the front axle. If you really want selectable hubs you are gonna have to swap to a non-jeep dana 44 or bigger from, say, an older chevy truck or a scout. Selectable hubs would be nice, but let's face it, it's not feasible on a jeep. it's the one thing jeep did to not make us have to get out and lock it to leave the road.
"Si Vis Pacem, Para Bellum"
'98 ZJ Limited V8 "Daisy"