Hello, I have a 2002 Chevy Silverado 1500, short bed,half ton 4WD. It has the manual floor shifter for 4WD, and auto transmission. Yesterday I had to use the truck in 4WD to get through a muddy area. While trying to engage the 4WD, I heard a loud clunk coming from the transfer case, and was grinding when trying to put the shifter into 4WD high. The shifter felt kind of loose, and when putting it in 4WD drive high, it didn't seem to be in 4WD. Then I shifted it back to 2WD, and the loud clunk was heard again. At first, the vehicle wouldn't move at all, and I had to put it in park, then to drive to get it moving again. Also, throughout the whole fiasco, the 4WD icon on the dash was flickering. I drove it home in 2WD fine, but when I got home, I tried to put it 4WD H again, and the shifter grinded loudly, and clunked again when putting it back into 2WD h. Does anybody know what the problem could be? Also, can I safely drive it in regular 2WD mode around town?