Durango 4x4 problem

From : bill

Q: the other day driving in heavy rain and standing water i used 4wd hi on my 2000 durango. now it appears that even though it is back in 2wd according to the selector and light it is still running in 4wd. at first it acted as though the front wheels were locked as it took over 1200 rpm to get it to move at all. after shifting from 2wd to neutral to 4wd lo and back again the front wheels freed up but now at highway speeds there is a high pitched whine coming from the front end. also after putting the selector in neutral i cannot move it unless i place the transmission in r or d then back to park or n which causes a very loud grinding sound from the transfer case. after which the selector will move back to 2wd. any suggestions would be appreciated. of course the warranty expired last month. thanks .