Rear Differential

Hello,
Just curious about something. When I was getting ready to change out my rear differential fluid, I noticed that there was moisture around the breather vent valve. I looked at the vent valve and it looked pretty covered up with black residue. But I was still able to push it up and down and move it around. I went ahead and changed out the breather vent valve with a brand new one. I also noticed a small amount of moisture at the bottom of the rear differential gasket area and a tiny bit around the pinion area. I’m still waiting for the delivery of my rear differential fluid so I can change that out next. Has anyone experienced this type of moisture, especially the one around the vent valve? Or have any thoughts on what this might be? Thanks.

 

Bump.

This is something I am curious about too.

 

Have you done a lot of water forging...?? Or naw?