When I installed my superlift kit, I went to Ford and purchased The spring/plastic retainer that holds the end of the CV shaft tight in the knuckle. It's a plastic style washer that has snap-ring plier holes in it, and around that washer is a spring. It's a pain in the azz to get out, and my suggestion would be a long set of pick's. Also there is a seal that is pressed into the knuckle in front of the cv boot. It's basically inbetween the cv-shaft and the hub, inside the knuckle. I would replace that and the spring washer setup. THey aren't cheap, I think I had to pay almost 30 bucks for the spring washers.
You can also upgrade your hubs to AVM/Ridgeline manual hubs if you have a truck that has VACCUM hubs, which is trucks 98-MID 2000 model year. I've had good luck with them, I know if I'm in 4wd, there is no guessing or hoping that the hub engaged. SEARCH AVM and you'll find all kinds of posts. The special tool could be 2 different things. One is a torsion bar puller, which is expensive, and there are alot of posts on here that show you how to do without buying the tool. And the second tool is a actual hub snapring tool, which I Have never been able to find at 6 different dealerships. Hope this helps you out bud.
I just found this pic (thanks matt) of the end of the CV shaft. You can see on the end of the shaft there is a race (sp?) that is where the plastic washer/spring assembly snaps into which keeps your CV shaft from moving around inside the knuckle:
This is what the inside of the hub looks like:
Here's the picture of the plastic/spring washer that is a PAIN IN THE AZZ to get out. This is also the piece that ford says you have to
have a special tool to put on which you don't need. I would suggest getting NEW ONES, cause you'll probabley destroy the old ones trying to get
them out. And the Flat part of it, goes inboard, and the side that has the ridge face's the tire.