Why do I have so much play in my steering wheel when I'm driving?

I have had the same problem on the steering box there should be a nut with a allen key slot in the middle loosen the nut and turn the allen key clockwise keep the wrench on the nut so only the allen turns tighten it about a turn to turn and half then retighten the nut and test it should help your problem.

Check the tie-rod ends and other steering components.