Ball Joints

I have an 2004 F350 6.0ltr Diesel. I think I need to change my ball joints. Is there a specific way or tool I need? Also, I notices a minor amount of fluid leaking out from the axle tube on both sides. I imagine that I need to replace the inner seals at the pumpkin. And last, the switch on the dash that puts the truck into 4 wheel mode, does not seam to lock the hubs. I have to go out and maunally lock them. The hubs were in the auto position, so what gives? Thanks