started a few days ago while driving uphill in 3rd and 4th gear would have a clunky sound like change in a dryer, very random, not a steady sound. the sound would increase when accelerating. now its doing it in every gear only after I engage into gear and accelerate. it sounds like its coming from the transfer case or rear diff but cannot tell for sure. in neutral does not make that sound when pushing the gas. sounds like loose gears or something, and it almost feels like its making the truck bog down a little like its starting to miss?