The joint is covered with TM 9-1803B (covers the three used by the jeep during the war), so it’s not too difficult to work on these… with patience.
What goes into the knuckle? This is a question that comes up repeatedly on G503.com. I’m not sure we agree with the answer.
The manual and lubrication guide say to use CG grease. This is a general purpose grease, either No. 1 for temperatures above 32F or No. 0 for temperatures below 32F. This is pretty much the same grease you would use for wheel bearings (except it requires No. 2 grease).
I have Rzeppa’s knuckles and they’re not that hard to take apart and clean and then put back together (although it’s a puzzle and I wouldn’t want to have to do it blindfolded).
When disassembling the knuckle, do not reuse the old seal. They are not that expensive and it is relatively easy to install.
Now there are others that would have you put a liquid or semi-liquid on the shafts. I’m not sure why. Putting grease on the knuckles has never made them “dry” in the 26 years I’ve owned my jeep…and I’ve taken the axle apart one too many times. These people use “knuckle pudding”, you just mix a little fat and a little oil together, mix until smooth but runny and then all you have to do is drizzle it on like a spread. Personally, I trust the original manufacturer’s instructions…and for 26 years I have never had a leak…well, in the steering knuckles anyway!
In the differentials, use what is specified by the manufacturer. All parts (transmission, transfer case and differentials) take SAE 90 (32F and above), or SAE 80 (32F to 0F) or SAE 70 (below 0F). I’ve compromised here and generally go with a “mixed” mix classified as 80w90. You can also find 75w90 but I doubt many need it. And of course at places like NAPA you can find straight 90s. But stay away from things like 80w140 as this can help your components generate excessive heat and lead to failure. I think this is what I was running (before I knew better) when my T-84J transmission suffered a major group gear tooth failure.
If the knuckle is a Rzeppa, I’m sure it won’t break in your hands, unless it’s damaged. I usually do the work alone, so I don’t have three, four or five hands to help.
Read the manual, read the manual, and then read the manual… ask questions. Have to! You will be surprised how easy this is. I took apart all the knuckle and kingpin assemblies and installed all the new parts and adjusted the tension etc. It took me a while, but it wasn’t that hard.