I just changed the gear oil on my rear diff last night, when stirred around it had a silverish tint to it, no metal shavings, but more like a metalic paint ish sort of deal. It does have the tracloc so I'm wondering if it's just the clutch pack as the gear surface doesn't look much different than the front, no chips.
Oh, and it's only been in there for about 20k, no foam(water) The front looked brown, no silver to speak of, but it's open.
Is this normal?