front 4x4 hub
 

I drove truck in rain today when i got home i noticed the ft right wheel was covered in what looks like rust. looking underneath from center of truck I can see rust around the hub where the inner bearing rides. i jacked up both sides and spun wheels and checked for movement. both sides feel the same and there is no noise or freeplay noticable. truck has 112K miles on it. Has anyone had problems or changed out hub bearings how difficult is it?