Closed knuckle lube issue
 

I’ve got the stock closed knuckle D44 8-lug on the front of my ‘65.

A couple years ago I had a local gear shop go through the entire front end and replace all bearings and seals. I had them fill the diff with conventional 90W GL-5 and the knuckles with JD Cornhead grease, which I’ve used in the past and am a big fan of.

I’ve topped up the knuckles a few times since to get the level even with the plug (kind of hard to do with the grease at room temperature). Between the new seals and Cornhead I have no external leaks, which makes me very happy.

I’ve drained the diff about three times since the rebuild and each time the oil has a green tint to it. I can see that there might be some contamination between the lubricants during initial assembly, but I’m not sure if the knuckle lube is continuing to leak into the diff, or if it just takes multiple flushes to get the green color out. Also not sure how compatible the Cornhead is with the 90W.

Anyone else out there have this problem?

Thanks
Tom

Re: Closed knuckle lube issue
 

Gear oil normally has a green tint to it in my experience. If you are certain you are getting cross contamination I would pull the differential out and check your inner axle seals for tears. It's possible a seal was torn when reinstalling the axle shafts. If they are torn, get new seals and get the proper installation tool (they are $30 or so on Amazon)

Re: Closed knuckle lube issue
 

Thanks for the input.
I know what you’re saying about gear oil color, but this is definitely John Deere green. I also suspected that maybe they weren’t so careful replacing the axels and tore the seals, but since an R&R of the gears is above my skill level, I really don’t want to tear it all apart until I know I have a problem.

Had a long and interesting talk with the guy at Torque King (one of the few vendors left that truly understands this old junk). His opinion was that the original seal design was intended more for keeping oil in the pumpkin, rather than keeping stuff out, and since the factory used the same 90W in the knuckles, preventing cross contamination wasn’t really a priority. Even though he sells his own version of “Knuckle Pudding” he knows lots of folks who use Cornhead with great success, and says it’s great stuff. Bottom line…he said some leakage was going to happen and to not worry about it. I have depended on them for years for advice and obsolete parts, so I’ll trust him on this and quite overthinking this.