I think it is in the right section. GM said to use a self-leveling heavy oil. Some folks here use corn head grease, however it is not self-leveling. It more or less liquifies under stress/pressure and then turns back to a heavier grease afterward. Cotton picker grease is a 00 grease which liquifies under use and then turns back into grease. These were engineered for farm use and the change in consistency is to help keep them from leaking.

I mix corn head grease with 90 weight oil to get a mixture that can be poured into the access hole on the steering box. It resembles the product GM used to sell but no longer does. Kind of like honey or the old STP stuff but not as "sticky or stringy". I'm not a fan of any product that changes back to grease when it isn't being used or when it gets cold. I've seen several steering boxes that were ruined from using the wrong stuff. You could also use mono-grade SAE 140 oil.

I'm sure there will be some suggestions very soon...

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end