Greasing A Manual Gearbox

Don't laugh. In the 70's working for a Dodge dealer we had lots of new cars with manual steering.
We found not many had much grease in them from the factory. A district rep told us to fill them with STP.
Did it make it easier steering ? It sure felt like it. Customers were happy. But a old box most will run out of the lower seal.
Seems that they all leak. I have white Luberplate grease in my 63 box.