This is a Sheppard M100 gear box.
I tried to take off the pitman arm with a puller, but I couldn't get a good grip on it. The puller would have came off if I tightened it any further. Come to find out later there is a special puller made to pull off pitman arms. We didn't need to take off the pitman arm anyways.
Here is the piston rack. When putting the rack and pinion gears back together, you need to line up the marks that are on the teeths. If you don't the gear box will not operate correctly.