From TM9-801 P87
(12) UNIVERSAL JOINTS AND STEERING KNUCKLE BEARINGS.
Every 1,000 miles lubricate with vehicle on level ground, with (CG)
general purpose grease, seasonal grade. If split type axle is equipped
with plug in hub driving flange, remove plug at steering knuckle
housing. Lubricate first through fitting in upper steering knuckle
bearing, and then through fitting inserted in hub driving flange until
lubricant is visible at plug hole. Replace plugs. To lubricate split
type axle without plug in hub driving flange, remove plug and lubricate
through fitting on upper steering knuckle until lubricant is visible
at plug opening. On banjo type axles, where two plugs are provided,
one on top of joint, the other one at front of steering knuckle support,
use only plug in steering knuckle support and lubricate through
fitting underneath joint until lubricant is visible at plug opening.
Every 6,000 miles, remove universal joints, (par. 167). Wash and
repack with (CG) general purpose grease, seasonal grade. Reinstall
(par. 167).
From Page 13 (part of LO 9-801 4 Oct 1948 Supersedes WDLO 9-901, 5 February 1945 ):
CG - Grease, General Purpose (above +32F CG 1) all other temp ranges CG 0
Now, what is the modern equivalent of CG 1 for use in the steering knuckle? Jeep guys go on and on about it, and one supposedly well informed 600+ year army educated 'expert' (in what we have yet to find out) go on and on and go no where.
Here is the answer.
First, modern grease is not the same as grease from 1940-50. So if you can (or say you have pallets of) either CG-1 or GAA then use it. But I doubt that most CCKW owners care or would go through the trouble to source such grease.
Why use a grease rather than an oil? This is a simple question. Oils need tight seals otherwise they leak. The steering knuckle has a very large movable surface area that needs sealing, also the brakes must be protected from contamination and so does the differential. Oil seals work great for that.. but sealing a small diameter shaft with a neoprene (or even leather) seal is no big deal. But a large curved surface exposed to the road/dirt/environment is difficult. A grease is uses becuase they stay in place (and stay where they are needed), and you no longer need a fluid tight seal. Also, unless the joint is submerged, you need a way to get the oil to the joint.. either with a splash system or a pump. A grease will adhere to whatever you put it on and say there till removed.
Now, the biggest stumbling point most people have is that a WWII MV was constantly serviced. If you note on the LO the majority of the lube items are either 1,000 mile (for simple lube) or 6,000 mile for clean and repack. That means that the grease is not designed (or able to) last for over 6000 miles of service.
Lets jump to modern greases. Most vehicles are not designed to be lubed. Long gone are zerk fittings and all bearings are sealed and lubed for life (life being approx 100,000-150,000 miles). Why is that? No one is going to run out every 1,000 miles and grease, or pack bearings every 6-10k. The advancement in greases designed them to stay put, not wash out and last for many, many thousands of miles.
So, what to put in a CCKW (or even a jeeps) steering knuckles? Simple.. follow the procedure and pack the CV joint with a good bearing grease (I use 707L red bearing grease) and fill the knuckle as directed with it. The modern wheel bearing grease will stay in place, lube the balls of the CV joint for many thousands of miles. When was the last time you relubed your modern vehicles CV joint? Answer - NEVER (unless you had a repair like replacing a boot.. then you might as well do it cause the joint is coming out anyway).