Are you entirely sure it's the steering box? Have you checked everything else, the steering shaft is a commonly overlooked culprit, and of course the usuals like drag link and tie-rod ends. Spring bushings will cause slop too....
Here's a blurb I wrote from a while back..
The common problems are:
Problem:Worn Tie-Rod ends
How to Check: Raise front of truck, grab a front tire on the fore-aft axis, wiggle and watch for tie-rod slop
Problem: Ball Joint Wear
How to Check: Raise front of truck. grab a front tire on the up-down axis, wiggle and watch for ball joint slop. Lower truck, watch for any movement in ball joint slop as weight is transferred onto wheels from jack.
Problem: Loose Front Wheel Bearings
How to Check: Same as for the ball joints, but the tire wiggles too much and you don't see the play in your ball joints, your wheel bearing require adjustment for replacment.
Problem: Drag Link Wear
How to Check: Raise front of truck. Have a helper turn the steering wheel back&forth while you hold on to the front drivers tire, watch for slop in the drag link. Also grabbing the drag link with your hand and wiggle can show the wear sometimes too.
Problem: Loose Collapsable Steering shaft
How to Check: Get two pairs of vice grips, clamp one pair on lower section, one pair on upper section, grab both pairs and attempt to wiggle in opposite directions. If ANY play is detected, replace the shaft. This is the most overlooked piece of the steering system and usally is the second most common cause of loose steering on these trucks.
Problem: Loose Rag joint
How to Check: This isn't as common. Raise front of truck. Have a helper turn the steering wheel back and forth while you watch the rag joint. Look for play.
Problem: Cracked Frame
How to Check: With truck on ground, have a helper turn the steering wheel (Truck can be running for power assist) and look for frame wiggle in the area of the steering box. Also, with engine off, simply inspect the frame around the steering box. Cracks usally show up on the top of the frame rail and just infront of the forward bolt holes (hidden, unless you can weasel of look at the inside/back side of the frame rail, which usally requires a mirror)
Problem: Spring fasterns/bushings/mounts
What to do: Tighten your spring and axle fasteners, they may be loose. Check for bad spring bushings front & rear. Check the sway bar bushings as well. If you've put lift blocks on our front axle, remove them, they are dangerous and illegal in most states and a very likly cause of loose steering.
Myth about steering box adjustment:
There is a common myth that adjusting the allen bolt on the top of your steering box will tighten steering. This is just a myth. What is will do is place more preload internally on the sector shaft and cause you to have to put more effort into turning the wheel (More torque required to turn). It will not remove any "play" from the system. If you have sloppy steering or the truck is wandering and tough to control, adjusting this WILL NOT help you at all. Additionaly, if you adjust it improperly, and place too much pre-load on the sector, it will break, leaving you without steering, and in a potentially very bad situation. People like to belive this myth because it is easy and free. But it won't help with sloppy steering. So avoid it. Adjusting this properly requires removing the box and putting it on a "tool" or machine that will tell you exactly where the pre-load should be. It is adjusted at the factory and requires no furthur adjustment.
