Front knuckle grease

[GJK]

I,m making progress on my 53 m38a1 restoration. My question, What type of grease do I use for the front knuckle joints? Thank you. Gary

[Zane]

GAA Grease is the original grease used by the military

[wesk]

GAA isn't much help for a guy shopping at the auto lube counter.

I believe you asked this question on the G503 page the other day.

First off the manuals do not agree on what lube to use. Military manuals say chassis lube and civvy manuals say gear oil. The civvy manuals reference chassis lube "0" or "1" weight for most of the lube points but they specify Universal Joint Lube (1 summer & 0 winter sodium base only) for the steering knuckles in the early manuals and the SM-1046 dated 1971 says GL3 SAE 140 summer and winter.

Chassis lube works but creates a heckofa lot of rolling resistance at zero degrees F. Not to mention the increased steering effort.

Gear oil in the 140 and higher weights will work on very new condition knuckles with real smooth sealing surfaces in most climates. But to make it not leak in southern or very warm climates on less than new knuckles requires a higher visocity. You can find higher visocity lubes like Ford model A gear lube (600 weight) and Penrose Lube (1000 or 1500 weight).

The next thing to consider is use and maintenance. How and where you drive will affect both lube selection and change interval. The average in the civvy books is check evry 2000 miles and change every 12,000 miles.
The military manuals use 1000 and 12,000 miles.

Finally there is the ole wives tale stuff they call knuckle pudding. This is a mixture of chassis grease and gear oil. Those who support this plan have their own recipes. I think it's really a case of indecision which causes some people to be unable to make a firm decision/choice so they pick both.

I feel that mixing odd lubes together is not a good idea and could result in one lube having an adverse effect on the other if they are not compatible. I prefer to pick the one that meets the demands my jeep will put on it.
For temps that stay above 80 degrees F I prefer a light weight chassis grease. Up here in northern Wisconsin I prefer the 600 or 1000 weight gear oil.

An important point to make here is when you open the knuckle up for the 12,000 mile repack you really should hand pack the pivot bearings (king pins, steering swivels) with chassis grease and the universal joint itself (load bearing surfaces) with chassis grease. Then fill the housing after assembly with the lube of your preference. I would not use any gear oil under 600 weight since when hot this will get thinner and have a tendency to dilute the chassis grease on the pivot bearings and it can also migrate easily into the brake shoe area.

[Zane]

i never said you could buy it at autozone i said the military used it

[Ryan_Miller]

What about CV joint grease/lube?

[wesk]

Relax Zane, My comments did not say you could buy GAA at Autozone either. My comments mean a guy needs the equivalent civilian spec to shop for a replacement grease for GAA. Or he can buy 40 year old cans of GAA from surplus dealers which in my opinion is not a wise choice. There are modern and much improved lubes that will work fine out here.

Ryan, The manufacturer recommends a sodium based lube and also GL3. So any lube meeting those basic requirements will work so long as the viscocity holds up under the jeep's normal operating conditions.

[GJK]

Thanks for the imformation. Gary

[TomM]

The Model A guys have sources for 600W but where do you go to buy 1000W?

[wesk]

Penrite semi-fluid grease.
http://www.penrite.com.au/html/s02_arti ... _top_id=61

US Supplier:
http://www.restorationstuff.com/Product ... ochure.pdf