2005 kenworth w900l Steering issue, steering box replacement?

Get the front wheels off the ground, engine off and turn the wheel. Does it have changes in feel while turning the wheel? There are other exceptions than Macks and I don't remember about W900's.
What is the bar and link arm?
Roll your truck forward on a flat surface and stop, no brakes. Put a mark on the back of each steer tire, at the height of spindle center. Thumb tacks work well and measure to the outside of the heads. May have to be off a little to miss the springs. Use two people and a tape measure. Start on the 10 inch mark, it is easier to be accurate. Roll the truck forward 1/2 tire revolution, get some help or use pry bars behind the drive tires, and measure the front. Looking for the front to be the same or 1/16 in, closer, max.
Mr level and tape measure are your friend. They never lye. Computer alignment machines have been known to. That is just a quick easy free way to double check if it is within reason.

 

Wmhow do you tighten up the steerning wheel when you have too much play? Is it on the gear box? If so where?