Best bet at this point is too clean out whats there now before introducing a new grease to the mess.
If you really don't have the time or know how to clean and adjust the box, and its working good with little or no slop, you can just add to it. Add a mixture of 50/50 axle grease and gear oil pre-mixed in a cup. It will end up being about as close to steering box lube as you can get. The Corn head grease is a #00 grease which is self leveling. All that means is that it will return to level as it sets, normal axle grease will stay where its pushed out of the way, the #00 grease will return to where it started from. My 1940 steering box holds one whole grease gun tube of grease. I would bet yours holds about as much or slightly more.
Gear oil in itself is to thin, and if your gear box is like about 90% out there, it will leak out. By adding some grease to it, the old seals can retain more of it.
We do it yourselfer's like to rebuild and clean stuff and steering boxes are kinda fun to work on. A off the truck cleaning and adjusting will make a tremendous different in how the truck drives.
Joe
