steering gear box

Can someone please assist me in explaining how to adjust the steering gear box in order to help eliminate front end drift on my 1998 GMC suburban. I have 187,000 miles on my vehicle. I have completely replaced all components such as tie rods, upper/lower ball joints, idler arm, pitman arm and alignment and continue to have front end drift. I was told that I should adjust the steering box but I don't know how.Can someone help me out. Thank you!

Only consider this if the box has play in the straight ahead postion, then at this mileage it may not work, to remove the play on a badly worn box may generate a condition where it will not return to center, anyway make sure the box has play in it first and post back.

Thank you for responding to my post. The play in my steering turned out to be a worn pitman arm.