Mostly just crud, although the truck started out in MI, then went to CO, I bought it in VT 5 years ago, moved to AZ 1.5 years ago, so yeah there is a little rust, but just surface rust . . . It's a truck, and I drive it like one, we have lots of dirt/gravel roads around here too, when I clean it I only polish the shiny top part! I don't even spray the hose under there anymore since I don't have to worry about salt!

I did clean them, (removed all grease) and looked inside the cage to see the roller bearings, all surfaces are smooth, and not pitted, same with the race . . .