Jimmi, that tan goop is GM steering gear lube GM part number 1051052. The last of it remaining in dealer stock was sold in 2006. Shell Oil has an exactly equivalent product called "Shell Alvania EP 1 Grease 2041SIPA".
I use the Shell product in the Vega steering box in my street rod roadster. It has the consistency of mustard, just like the GM stuff, unlike chassis grease that is more like peanut butter.
In my '36 Chevy pickup steering box I machined the sector housing for an oil seal and use gear oil as a lubricant. Because of the seal the oil stays in no problem. In fact I haven't had to add any since I made the oil seal conversion and filled it in 1974.
