View Full Version : Closed Knuckle and Steering Box Lubrication

03-27-2020, 07:51 AM
This is what they came filled with. An S.A.E. 140 grade, multipurpose gear lubricant meeting the Mil-L2105-B specification. This is NOT the same as 140W axle gear lube, It is called Gear Lube but we are talking a different gear type. Not axle gears. It usually leaked out in a few years. Do not use 140W axle gear or Transmission gear lubes, they will leak out much faster, and not provide the correct protection. Note this would have been put out to bid to vendors when the Jeeps were new. The vendors would bid on the specification above. It is an EP lube. It is the same lube for the steering box.

If you are sticking with the "Bendix" type joint or, open bearing style and a sealed knuckle, make sure you use an EP type grease. All types of automotive "torque transmission through an angle devices" require Extreme Pressure grease. If you google Grease for Closed Knuckle Axles and Manual Steering Boxes you will get a few choices. The lube is referred to sometimes as a "0" lube or a "00". It is the same stuff you might be using in your steering box. It cannot flow. It needs to be thick like honey. It reminds me of STP engine treatment from the 60's and 70's. A little thicker, for the steering box use https://www.ecklers.com/champion-00-manual-steering-box-grease-57-376792-1.html?utm_source=google&utm_medium=cpc&adpos=&scid=scplp57-376792-1&sc_intid=57-376792-1&gclid=Cj0KCQjwt4X8BRCPARIsABmcnOphnna25XoiCzQVr1Lm DvFP2DtiqGDdoxM5fPQOKu1sNu-EvWqs6cQaAlOeEALw_wcB

There is a lot out there on what to use. Use something made for the closed knuckle Dana axle. Don't mix your own. Here's the deal. The knuckle cavity is "sealed" by the gaskets, wipers and seals. The "King Pin Bearings" are not and, the U-Joints had their seals removed or, are not a sealed design.The idea was to run everything in a bath of lube. A large bath of lube. This was good when it was OK to loose a little lube to the environment, as long as you refilled. They leak. Use something like this https://torqueking.com/product/777/closed-knuckle-lubricant-for-closed-knuckle-4x4-front-axles/

Here is what I recommended at Tech Service to "Closed Knuckle users" that wanted to "upgrade". Treat the king pin bearings like wheel bearings. Pack them well and install. Use SEALED re-greasable or, Lifetime lubricated non-greasable U-Joints. USE all the seals and gaskets. This will create a "Dry" sealed environment. You need to remember that if you do this, you need to re-pack the king pin bearings every now and then and, grease the U-Joint if it is greasable. Wet the felt seal with some ATF so the seal wipes the knuckle easily when turning. For u-Joints I prefer the top of the line SPICER sealed Lifetime non re-lubeable 5-760X. They are the strongest and, will last a long time. They are not cross drilled. This gives them a higher torque capacity.

10-11-2020, 06:59 AM
The lube ratings can be so confusing I am adding this to the conversation. The S.A.E. specification of 140 often gets confused with other 140 specifications. Compounding this the old Mil Spec of MIl-L2105-B is very broad. The "B" however changes everything. The way the Society of Automotive Engineers (S.A.E.) rates oils is complicated and has a few requirements to group oils, grease and lube. You can have an S.A.E. 140 in your axle that is thick but pours nicely. The S.A.E. 140 in the steering gearbox however is like petroleum jelly. It does not pour. If you were to apply the testing requirements to both lubes to get the S.A.E. rating, they would pour the same. One of those main requirements is the temperature of the grease under testing. The 140 axle lube and the 140 steering lube act similarly under the testing temperature and parameters. In real life the steering box/knuckle lube will never get as hot as the test. In addition when it is at room temperature it is like jelly where axle lube is still liquid. They are both still 140 however.

I hope this helps, suffice it to say all S.A.E. 140 lubes are not the same. Think of the S.A.E. rating as a pour ability at a certain temperature, for lack of a quicker explanation.