I believe I have identified the steering wheel play to the gearbox. I say this because when moving the wheel through its' free play(about 2" each way), the pitman arm does not move. It is my understanding that indicates the gearbox to be the problem. I've read conflicting articles on adjusting the steering box with some saying to adjust it with the wheel all the way turned in one direction...others saying don't bother...others saying just to loosen the lock nut and turn the screw in 1/4 turn. I don't want to damage the steering box with improper adjustment.
Keep in mind that the sector shaft adjustment affects the entire range of travel - you can't adjust the clearance for just the midde of travel, for example.
Unless you're driving in circles, the sector and rack nut spend most of their time at the center of travel, so that is where the wear will be greatest. The least amount of wear will be at the ends of travel. Over time, the sector will no longer form an arc centered on the shaft rotation point, and the rack will not effectively be straight. (I'm talking about the line described by the points of contact on the teeth) What this means is, you will have play at the center of travel, and reasonably good engagement near the stops.
Adjusting the sector shaft with this condition, you can take up the play in the middle of travel, but now there will be insufficient clearance or binding at the ends of travel. You might be able to find a point that reduces the play to a tolerable level without binding at the stops. If you adjust too far, you will damage the teeth on either or both components. On the other hand - they're already shot. Once the wear reaches a certain point, the only way to correct it is to replace the sector and the rack nut.
Theoretically the teeth could all be reground to a depth equal to the point of maximum wear, but even if you could find someone to do that it would be
Expen$ive.