If your ball joints are bad, you may wish to have someone with the right seal drivers do the job (ie. the Ford dealer). The ball joints are straight forward, but to pull and replace the axle shaft on each side involves changing a vacuum seal that has to be installed correctly (with the right tools.) Failure to install the seal correctly will result in a vacuum leak in the four wheel drive actuation and water entry into the hub area (where water doesn't belong.) Otherwise it would be an easy job.