Ford Excursion :: 2001 - Steering Sticking - Won't Returning To Center

My 'new to me' 01 Ex has 129k miles on it and the one problem is the steering. I read (all 34 pages of) the wander cure thread and I played with my steering box extensively over the last 3 weeks. The initial tightening really worked with the slack in the steering, as did adding air to the passenger front tire to even it out with the driver's side. But it did not cure everything. In fact, the tightening of the box revealed something else - the steering now exhibits what feels like binding. And now I must make minute corrections every second or two all the way down the road, even perfectly straight, flat roads. It's sorta driving me crazy(er) and my wife won't even consider driving it until it's fixed.

I was so caught up in diagnosing this problem that I completely missed that the steering wheel would not re-center itself after turns. My father noticed when he visited last weekend and tried to drive it but parked it after going around the block. If making a 90 degree turn, the wheel will maybe make it back to 45 degrees and stops. So you must manually turn the wheel back to center if you want to go straight.

So I've gone back and tried to loosen up the steering gears to start again, but now the gears seem tight regardless of how I adjust it.

I have already planned to replace the ball joints and get the alignment adjusted when I do the shocks and rear sway next week. Should i wait to see if the ball joints fix the problem or should i plan to replace the steering box at the same time? What say you all?