Rear-End Wear?

[Doughboy21kd]

I pulled the fill plug on the rear end and noticed there is a very light grey, thinish layer of shavings(if that) more like a paste on the end of the plug..... I am just wondering if that sounds like normal wear?..... Truck has 12k on it..... What ya think?

 

[YFZBOB]

It's normal wear. The Gear Oil has no filtration. Particles suspended in the oil just gets recycled through the gears. Eventually turning it into Dust. (Paste) I changed the gear oil right around 4K, the first 3K mile or so is where the most wearing will happen. Replaced the stock cover to the Mag-Hytec Differential Cover and added synthetic oil.