So anyway, apparently the 231 does not have a biased link between the front and rear outputs when not in "locked" mode, so if you do have the 231 my advice prior is incorrect (would be correct if you have the 242 "selec trac).... but here is some good reading material if you want to learn more about the "command trac" or NP231 transfer case
http://4x4trailhunters.com/article.php?id=20
and
http://www.novak-adapt.com/knowledge/np231.htm
Oh, one other thing I would mention, seeing as how there seems to be some thoughts on this.... There is absolutely no major difference between the 231 the KJ uses and the 231 the Wranglers have used and use. Mechanically they take the exact same part numbers and everything (from my research anyways).
Later,
-Adam