Front passanger side wheel

I have a 98 isuzu rodeo and the front pass. Side wheel sounds terrible kinda of grinding noise, almost like im dragging something. I can push the 4wd button and this noise stops. I used to be able to push the 4wd button and move forward and then push it again to disengage and then back up and this would cure this noise for a while. Seems like the noise would come back when I hit a big bump. But now it will not stop making this noise unless the 4wd button is engaged. Thanks