It should be packed with grease. That is, basically it should be full of grease, leaving room at the top. This done when the gears are out.
Keeping it full in service can be handled differently:
If it wasn't sufficiently packed to begin with, try adding more grease. The problem is that NLGI #2 (or even #1) grease doesn't flow downward with gravity. Therefore it may leave the gears or portions of it in an air pocket. Eberg's 50/50 will reduce that possibility, although some of the oil may drip out over time.

If the oil has seperated from the grease and dripped out, then add a gear oil. Grease works as a lubricant because it holds oil.

I have not found the specs for the Chrysler lube. I had some luck finding specs from Ford and GM for their very similar recirculating ball steering gears. NLGI 1 seems to be fine except in situations where the box gets very hot. NLGI 2 seems to be the prefered thickness where exhaust runs close or the engine compartment was tight. Whatever you use, try to make sure the base stocks of the greases are compatible.