if you ask mopar: "that's the way they are!" LoL
I have have been fighting the wandering issue since I got my 94 2wd in 1999. I tried alot of things, that which appeared worn and even that that did not. I was so close to selling it, but had too much invested too. More money down the hole.
To the point:
First of all I can't speak for the steering box company that these guys talked about but I I know that I tried one from AGR. It was not that great, infact I took it off after a few thousand miles, cuz it wandered as much as the mopar original at 120 some thousand. I dont remember too much about dates and mileage unless I look it up, but it was around Feb 02.
I ended up rebuilding mine with the help of a mopar junkyard owner. He's see and done alot. So I trusted his help. We replaced the output shaft needlebearing with a timken. Reset the preload/specs. Oh, btw the only real way to set preload is to have the box off so all the oil will be out of it. It preload is only in the range of a few inch/lbs. so you can see why it has to be on the bench to do this.
I took the AGR off and put the factory one back on. It was better but not great. Let's face it these Cummins are heavy, so keeping them stable is a chore.
Eventually I found more info off this site for a company that makes a bracket to help stablize the output shaft. This IS where most of the problem is occuring, most likely. If you want to check. Try this, but do it safely, cuz i am not responsible for accidents. ( my internet disclaimer )
You can jack truck up or if you can get underneath w/o doing so ok. Just if you raise the truck, lower it back down on some nice size 8x8's so the weight is back on the front.
with truck engine running, get under, reach up and turn input shaft some. 1/2 turn whatever. View the output shaft. it will move side to side, in excess of . 060 perhaps. If you see this happening this is the start of your troubles.
If you want to try to stablilze this go to
http://www.solidsteel.ca/
You can do what u want. But this, along with a nice set of Firestone regular tread, not the all season tires, helped out the most of every thing I did.