rlo

So far changed my differential fluid twice at about 25K each time. First time around there was a thick grease sludge on the magnet drain plug. Second change still had it just not as much as the first time.

I was curious will the drain plug ever come out clean or will there always be a certain amount of sludge in the differential because the amount of miles that the gear oil undergoes compared to say engine oil?
Also does it matter if it sludges a little? Since the differential is sealed it doesnt need to circulate the oil, its just providing a nice pool for the gears from how I see it.
Looking for thoughts, advice, opinions.

TVPostSound

iTrader: (9)

The sludge is the fluid mixed with pulverized metal. Shouldnt be too much.
Perfectly normal, gears wear over time, no matter how good the lube is.