If you can repeat the problem after it is removed, that's what you want to do. BUT if you get it out and you can't feel the movement you describe, you will not know if it's fixed. That's why I gave a list of possibles other than the box itself. You have not verified those checks/questions..
If all is good regarding those checks and you feel like the slop will be evident on the bench, then remove and begin careful disassembly. If you installed the column then you know how to remove.
One more check I forgot, if the steering wheel is not on properly or washer not on or something up top is not assembled correctly it could possibly allow for slop.
More than likely it is internal box problem, just want to be sure before you dig into it that it is not an external issue.
