55 Wasp Steering Box Adjustment

supercub

I had some end play in my steering box. I could see the shaft moving up and down when the wheel was turned back and forth. The manual describes removing a shim from the top cover plate but it didnt seem like there was. I noticed that the large bolt on top was loose and tightened it a little, and that got rid of the play. There is a star shaped plate below the bolt that would seem to be a lock for the bolt if bent against the hex. The star does loosely engage with the boss around the smaller nut next to it. I bent it up to the bolt but it can still move around, it should be fine. 
Hudson must have used a totally different steering box than the one described in the manual. I would still like to change the gear oil in it. Has anyone done it before on this type box?