4 Wheel Drive/SUVs: 4wd noise, side kick panel, transfercases

Question
Sir, My wife has a 98 Chevy S-10 Blazer thats giving her problems when driving down the road the suv starts to make a whining noise from transfer case area when you push the selector switch to 4Hi noise goes away then you can go back to 2hi you can hear the transfer case module in pass side kick panel clicking when pushing the buttons I have pushed the selector butons when sitting still and can hear acuators working on case and front diff. what could it be? your help will greatly apprieciated.

Answer
Rick, alot of times what happens to these transfercases is they get worn inside especially the forks, and the plastic fork covers , which could allow this blazer to try to shift or engage while moving , my dad rebuilds transfercases all the time , and this is very common, ThanksADAM