For what it may be worth, the only time I've seen one of these steering boxes actually need rebuilding was after somebody had filled the box with what looked to me like chassis grease and used it for a while. Any sort of heavy grease will in cold weather and over time cavitate leaving the box virtually unlubricated. Others may and possibly will disagree but I mix corn head grease and 90 weight gear oil about half/half and use that. I don't want any grease in there that could possibly harden with weather changes, time or anything at all. One thing I'll say...using a thinner mix of gear lubricant may cause your pitman shaft seal to leak a bit. Won't leak much and more in the summer. You can replace it in situ but you will have to get the old seal out and that may not be as easy as you would wish. The old seal was nothing but a metal collar around a piece of felt. The replacement seals today are a rubber lip seal and do a good job. The last old seal I removed I finally got out after making a hook tool out of a small screwdriver.
A few weeks ago I topped off the old grease in my steering gear with some 80w90. I figured it would help loosen up any crusty old grease and then I could suction it out and replace with the bottle of cotton picker grease I have on the shelf.
Well, it looks like it “self-flushed” out the pitman seal and onto the garage floor. No big deal there. Am I safe to assume the cotton picker grease will mostly “stay put” in spite of the questionable pitman seal?
