Front differential breather/vent line hose
Just as a heads up as I was crawling underneath my truck I noticed a hose that was hanging down from the frame as I traced it back it was the breather line for the front differential. It had 3 to 4 plastic push in style clips that were obviously never pushed in or used anywhere. Assumming it never got installed properly from the factory and slowly singled its way down. Have a 5/16 build date. Might be worth a look.