Birf: why would grease migrate from knuckle to diff oil but not opposite?
OK, been wondering about something... Thought I'd ask you whizzes!
I see no knuckle soup seeping out of my knuckles whatsoever. When I opened up the knuckle, the grease looked just fine, solid, not soupy.
Now, on the other hand, I replaced the diff oil when I got the truck (was pretty greasy) and 3000 miles later it has gotten fairly black again. Unless there was some residual grease in there, this makes me think that some knuckle grease may have gotten into the oil. That would suggest a worn seal, maybe. But the only obvious reason I can see for that migration would be that the axle housing would have developed a vaccuum because of rapid cooling. This, however, is not likely cuz I have extended my breather and left the end open. Also, wouldn't a worn seal leak both ways?
So, is there any other reason why grease would move from knuckle to diff oil and not v.v.? What? Just rotation and capillary effects maybe? Or can the knuckle develop overpressure somehow?
OK, been wondering about something... Thought I'd ask you whizzes!
I see no knuckle soup seeping out of my knuckles whatsoever. When I opened up the knuckle, the grease looked just fine, solid, not soupy.
Now, on the other hand, I replaced the diff oil when I got the truck (was pretty greasy) and 3000 miles later it has gotten fairly black again. Unless there was some residual grease in there, this makes me think that some knuckle grease may have gotten into the oil. That would suggest a worn seal, maybe. But the only obvious reason I can see for that migration would be that the axle housing would have developed a vaccuum because of rapid cooling. This, however, is not likely cuz I have extended my breather and left the end open. Also, wouldn't a worn seal leak both ways?
So, is there any other reason why grease would move from knuckle to diff oil and not v.v.? What? Just rotation and capillary effects maybe? Or can the knuckle develop overpressure somehow?