are you sure the free play isnīt in the link from the steering wheel to the box... are you looking at the input splines when you move the wheel and the drag link? or are you just moving the wheel and watching the tires?

I havenīt measured how much free play there is normal, but I would suggest you look at the (lack of english word) near the steering box there is a cross thingy, I would think if there is possible to have free play somewhere it would be there. and there is also a croos inside  the cab, inside the steering column.

good luck