I had a problem like that several years back on a Ford F-250 and it was the tie rods that needed changing out. While on the truck you could not see any play, but after they removed them, I was shocked at how much play they had. I would not mess around with adjustments to the box, you could really mess it up and dangerous.
2002 Gulf Stream Scenic Cruiser
2018 Buick Envision Essence
Neway Freightliner chassis
Aventa II Blue Ox