Ok, thanks to CCjeresey I now understand why our signals are crossed. My male splines (on the hub/shaft) are sticking out past the sprocket 0.125. Now I understand why I couldn't comprehend the specs. and the way they worked. I was backasswards.

On the back lash- I did put the keyed hub back on and stuck it in as far as I could push. Everything seems quite stable, and the only movement I am feeling is the movement between the teeth on the pinion and bull gear which comes out in the neighborhood of 0.080. This is with my dial indicator set up at the top of the bull gear. Things don't look that bad in there to me, but what do I know? With my finger I can feel the face of each gear tooth and feel some wear, but I would assume that to be the case in a 60 year old dozer.

I don't understand why all the confusion:confused: the picture supplied early on should make it clear enough as to spline/sprocket position.
Your sprocket and hub is shot so lets move on to the next challenge:)

From what you describe the gears seem pretty good although the back lash is a little high. For occasional and hobby use they will probably be fine but I'd still like to see the pictures. In particular I'd be looking for signs of an even wear pattern across the face of the teeth (no wiping/diagonal pattern).

We haven't approached the subject of bearing condition yet. Can you post some pictures of the bull gear inner bearing and race, plus the outer hub/axle units and the exposed pinion bearing and race.

I apologize for not studying the drawing close enough. To get to the bullgear inner bearing and race I assume I have to unbolt the sprocket hub from the gear, correct? I will take pictures of the pinion bearing (that is still in the final cover), gear teeth, bearing/race on the end of the pinion shaft, and hopefully I can uncover the inner bullgear bearing and race. I'll get the pictures posted up at about 4:00. The camera is on charge.

Not necessary to separate the hub and bull gear.....you can remove as an assembly or separate now as you will be doing so eventually anyway. Pictures of the outer hub support bearing and race also plus the pinion shaft.....Basically get pictures of all rolling or rolled on elements.

Do the hub and bull gear pull right out now?

Yes.
That is one of the options to remove the whole works. If you had originally removed the outer end retaining hardware and unbolted the case cover the entire assembly slides off the shaft for service.....bit awkward and heavy but allows you to take to a facility that can do the press work. Might want to consider this when it comes assembly time. Otherwise you will need to have someone press the sprocket in the field.

Can these gears be turned by hand with the other side track still on and on the ground? Such as putting trans. in neutral and pulling steering clutch in? Or is everything just too heavy to rotate by hand?

Tying back the steering clutch lever (make sure brake is off) on that side disconnects the drive so you can turn the gears. Normally wouldn't take much effort but I'm not sure where you are with the hub & bearing support. Without anything holding the hub in I would expect the hub and bull gear to come out of the inner race.

Here are some pictures