I don't think I'd mess with the steering box until you've checked everything else. You can check it by disconnecting the drag link and checking for play in the pitman arm. There are a lot more items that will affect steering play besides the box.
Do you still have the barrel type tie-rod ends that are adjustable? I'd start there if you do.
Last edited by klhansen; 11/19/2020 9:45 PM.