when i engange 4h or 4l it goes into gear fine but when i start to drive i get this clunking sound from the front of my truck like maybe a trans axle is slipping or busted or the dif is either screwed or low on fluid im kinda new to the 4x4 i just got the truck, i know my way around the frame tho so any suggestions plz plz let me know thank you   and when i shift out of 4wd my light for 4x4 stays on until i get to about 45 mph. and then i t turns of UNTIL i start to slow down to about 40 45 mph. and then it sound likes its trying to go back into gear plz help!!!