switch light comes on as it should , no codes found . In 2 wheel drive I have an occasional grinding sound at any speed like gears trying to engage . When you switch to 4 WD there is no grinding noise but have no 4 wheel drive now . The noise is coming from possibly the transfer case area . I found that the front drive shaft going into the case is sloppy . Could this possibly be the bearings in the case causing this noise and no 4 WD or another problem ??? Maybe not engaging all the way .