Ahhh, I see. So ok, yeah, in order to install that whole unit, you will indeed have to drop the whole front axle. Or at least I think it would be pretty damn difficult to do it without taking the axle housing out completely.
This is where the frustration begins, because I had one serious hell of a time getting the axle to drop clear without removal of the steering centerlink. I am in the same boat right at this moment with my Trooper, switching to 4.77s and in the process of doing so, I have to remove the front axle entirely. For the life of me, I cannot get the axle to drop all the way, because the steering link is in the way. So I am now faced with removing it, which is a serious pain and will likely force you to replace it as well. I've never been able to get one off without mangling the boots.
The pisser in your case is that if you had two extra CV band clamps, you could just leave your axle up and do it from the inner CV out.
Good luck,
Bart