The biggest problem with 4x4 trucks is not the 4wd system or the tires but lack of weight on the rear axle. An empty bed is so light that the rear end can break loose super easily. If you have a pickup you need something in the bed to weigh it down. I used to load my Nissan 4x4 with about half a dozen bags of tube sand just to make it driveable on packed snow and ice.
I watched a truck do a 720 and get away clean (luck sob) today on the way home because of the lack of weight on the driving (rear) axle.