Looking at my manual it apears that axial play of the 107 input shaft is not adjustable. It looks like the shaft axial play is controled by axial bearing play of a single ball bearing clamped into place. Therefore steering box play is most likely limited to a worn bearing, worn ball nut or shaft, pitman shaft play or pitman output shaft bearing play or the ball nut and pitman gears themselves.

I would say that a good trouble shooting procedure would be to over tighten the pitman shaft. Then have an assistant rock the wheel back and forth. Look for axial motion of the input shaft or side to side motion of the pitman output shaft. If any of these two conditions exist they should be repairable with simple bearing changes. If not a new ball nut and input shaft and maybe a pitman shaft are required. The later items would probably best be handeled by purchaseing a rebuilt unit. Its hard to say but it looks like bearing replacements can be done without special tools.

One word of caution. Just because you find play in either bearing may not limit the problem to only those bearings, so a good inspection of the rest of the parts is a good idea.

John Roncallo