BAD grinding noise when 4 wheel drive is engaged and beyond

Over the past month or so, as it's gotten colder here, I've noticed that when I leave in the morning there is a sound that comes from the front drivers side wheel that almost sounds as if there is a stick stuck in the spoke and is hitting something (almost like that sound we used to make as kids by putting a playing card in the spokes of our bikes to make it sound like a motor lol). The faster I drive, the more rapid it gets. After about a mile, it stops. However, this morning I went to use 4wd for the first time for real (I do put it in 4wd about once a month briefly just to keep it lubed) and the same noise is louder, more consistent, and doesn't go away as I drive, BUT the 4 wheel drive seems to be working. The 4Hi light does not flash, and I get good traction, however the sound coming from that wheel sounds like it's griding gears for something. When I put it back in 2WD it goes away. However, remember that it does do it in 2WD for about a mile after the truck has sat overnight. I have no idea what this could be, other than a cv axle. It's not the sticker TSB some have talked about. This noise sounds like my front end is coming apart. Thank you for the help.

 

CV axle, wheel bearing come to mind

 

It could be the needle bearing.