Two questions: Hub temp and hitch lube

I can't imagine in my 40+yrs of towing that not lubing a metal to metal contact combined with friction isn't a wise idea. A Hitch Ball Cover will decrease your need of making a greasy mess of things. As far as the axle hub heat, a 100* temp seems to be a fair average temp. That temp is only based on you not using your brakes. Other than flat towing will your hubs feel only warm to the touch. As your driving habits began change, such as using your brakes more often will that temp begin to increase in temp. Myself I use a synthetic rear differential oil and a synthetic wheel bearing products to help in maintain lower operating temps. Synthetic oil is used in most HD trucks in the rear diffs from the factory.