Classic/Antique Car Repair: 1952 chevy pickup, line mechanic, oil seals

Question
what kind of lube should be in the steering gear box on a stock 1952 chevy 1/2 ton pickup?  I find a fluid port (similar to the one on the side of the tranny and rear end) but when I open it I find what appears to be grease.  Truck is new to me and I don't want to mix grease with gear oil.  The shop manual doesn't help.  Should I pump it full of grease or should I put gear oil in.  Neither seems like a good idea to me.

Answer
Gear oil is what was recommended when the truck was new but back in the day the oil seals wore out and the gear oil leaked out. So the common practice was to pump it full of chassis grease and away we go. yes I am old enough that I was working as a line mechanic when this truck was new. The chassis grease worked well except when the temperature got down below zero and then it took Magilla the Gorilla to turn the steering wheel.
Brad