[rotorwrench]

The Gemmer II steering box was a good design in that day and age. They wear more rapidly than the more modern units but generally last at least the expected 100K miles for that time frame. When you check the box for adjustment, the straight ahead centered position is the only place where the play should be minimal for this design. This is also where they tend to wear the most. If the gear gets notchy after adjusting to minimum play, there may be some pittiing wear in the center of the worm gear. If it is still smooth to rotate after adjusting, you will get a reprieve from further work and it will be good to go for the time being. John Deere corn head grease is a good lubricant for these units but with a good sector shaft seal, the heavy gear lube will work OK.