pitman arm pro comp question

[Duele]

hey guys I was just wondering how much space should be between the back of the pitman arm and the steering box. Basically I have a pro comp 6" lift with a vibration and had read online about people pitman nut backing off. mine is on there but there is about a 1/2" gap between the steering box and the seat of the pitman arm. Also I can see thread on the steering box shaft still with the pitman still on.should it seat higher up?. I know its tapered but I dont know how far it should seat up on the shaft.

[F350Powerstroker]

Its gonna have a gap about that far... Try putting a wrench on it and see if its loose! Have someone else steer it back and for while you watch it...If its loose youre gonna see it right away.