Differential Sludge

So I changed my differential fluid a couple days ago and was wondering grey sludge is bad. The oil itself was still a bit golden but the drain plug had a decent amount of sludge covering the magnet. There were no metal chunks but just little shavings on the magnet.

 

This sludge as you call it is actually very small metallic particles, suspended in lube. It makes a slurry of sorts. It’s rather normal and much better to see than bits.

 

I second that. Completely normal

 

Normal. It’s a diff. Those two gears inside have to touch each other. Metal to metal contact.