Front Diff oil poured out greenish gray and shot with streaks of Moly.... (1 Viewer)

[Rusty Marlin]

Crisis averted, I panicked.

! Looks like I'm joining the club of knuckle rebuilds, ready or not.

If anybody lives near Columbia SC and wants to learn how to rebuild front knuckles at the same time as me, drop me a PM. We'll muddle through it.
Gonna order the kit when I get home tonight, so probably gonna happen next weekend (27-28th) or over the 4th.

 

[pawnthatdude]

Green gray diff fluid is normal, as far as I have read, and in my own experience. What is the quality of the grease from the knuckle fill port? Dip a zip tie in there buckle first and see what the consistency is. Are your knuckles weeping?

 

[woodsman 44]

normal, I get this everytime I drain, a little birf grease will get by and into diff oil...just refill and drive

 

[Rusty Marlin]

Green gray diff fluid is normal, as far as I have read, and in my own experience. What is the quality of the grease from the knuckle fill port? Dip a zip tie in there buckle first and see what the consistency is. Are your knuckles weeping?

Should have done the dipstick test first... crisis averted, nothing to see here...
Came out black and gooey, nothing but moly-grease.
When I saw the difference between the rear and the front, I guess I panicked a little.
The rear looked brand new, its only been in there 20K, but we were in a LOT of water on the last trip and I wanted to be safe.

 

[rolliges]

Order the supplies anyways and double check (& raise) the axle breathers to avert a future real crisis.

 

[Bambusiero]

Yeah, I had that too, with a front diff lube change after way too long. I asked about it - Tools R Us explained that it is normal, due to the half shaft oil seal being sort of a one-way check valve (inward), and the birf housing has no vent, and gets a little pressurized when warm, so moly grease gradually migrates inward into the diff oil. No real harm in it, lubrication is extra good, except the diff oil is gradually getting it's viscosity increased above normal, and so it's cooling function might be somewhat reduced.
If the birf moly grease is still grease and not soup, then that means your seal is still OK. Birf too full with grease, and not enough air expansion room - would exaggerate this effect.

 

[ppc]

Sounds like a Wit's End knuckle housing breather is needed.