 hubs
the auto hubs dont work that well u can change the hubs out no problems just as long as its not a dually model hubs cant handle wieght what u can do to check your hubs is look over top of tire check and see if u can free spin axle shaft if u can the turn hub to lock postion if the axle stops turning and u can turn back to auto then hub is good check both sides the transfer case acutuater had problems in that year 1999-2001 hi can be
shifted in drive but low only in nuetral at a stop then drive,have someone in cab key on not ruuning u under truck with it in park rotate drivline while person in cab turns switch if drive line stops acutuater is good possible your hubs are unlocking them selfs if 1 hub unlocks 4wd doesnt work because its a limited slip,hops this helps | 
