I have a 2010 F150 XLT 4X4, and I took my truck mudding the other. After I cleaned the truck off I noticed a noise that sounded like grinding/glass in a blender coming from what I think is the front passenger side. The sound only appears when I accelerate my truck, not when I press the break or take my foot off of the gas pedal. Also the sound goes away when I put my truck in 4 high and 4 low. Any suggestions on what this could be?

 

I'll take a wild guess and say the front hub on that side might be stuck partially engaged.
Do you have manual or automatic hubs? I honestly have no clue as to what the newer trucks have, so that might be all I can do for help.