That's probably just oil, covered with dirt, oozing out.

My understanding from back when I had the 83 was that unless you've got oil running down the inside of your tire, making it to the ground, it can be ignored.

 

Thats great news. One less money pit to worry about, one step closer to putting my lil truck back on the road.

 

Yeah. Though hopefully others will weigh in. When I first got the 83, I was even less of a mechanic than I am now, and had a shop do the knuckle rebuild. I did have oil running down my tire. I don't remember exactly, but it took them one full day plus another couple hours the next morning, and I think it cost somewhere in the $600 range. On a truck I had just paid $1,200 for. Not a small job. Then I remember seeing it leak again right away. But in the next 3 or 4 years I owned it, it never got to the point of oil running down the tire again.

 

My take on this whole drippy grey ooze...first the grease used in these knuckles, molybdenum disulphate, (I'm not adding anymore to the grease discussion/specifactions after a "monkey throwing poo match with someone else here"!) has a tendency for the oil to separate from the base. I've even had the stuff separate in an un-used tube! 35 - 40 years of using it both at home and professionally its got to be one of the messiest grease out there. I now use Valvoline brand which has polyethylene in it. It would seem the polyethylene keeps it from separating, or maybe Valvoline brand is just better. Is it safe to mix the two together? I did, and I'm not worried about it.

So likely the "oil" you see is the grease separating. Gear oil has that un-mistakable smell to it. (Not getting into why it smells that way...see above monkey poo comment.)

Original FJ owners (FJ40/45 etc) never seemed to get worked up about this. Nor do (did) original 1st gen owners.

Now those knuckles are not vented as we would think venting is, so as the birfield joint in them spins and heats up the pressure needs to go somewhere. Well there are only two places for it to go, out the knuckle seals, if we can call them that, or past the inner axle seal into the differential. So its common as well to have the grease in the differential oil too. That's why when you drain the front diff oil it has a greyish colour to it. The inner seal is installed to keep the oil in the diff, not the grease out of it. Perhaps the "new" after-market rebuild kits have double lip seals to prevent/minimize this...I don't know as I've never used, much less seen one of these kits. That's why its important to keep greasing them the right amount. You're going to have to experiment on the right amount according to your usage. Toyota simply says, "repack". It took me roughly 20 years to get the right feel of how much.

Bottom line...if your axle oil doesn't continuously go down and there isn't a tube of grease puking out of each knuckle...l'd leave it...if it aint broke don't fix it! DO NOT pressure wash directly the knuckle seal area, your just forcing water in them. Just use the garden hose to clean off any mud and a solvent soaked rag to clean off the excess grease.

 

Very good info. Thanks fellas. You guys just saved me a couple hundred dollars!