So I haven't serviced the differential in my first Slash in a long time. So I was running it yesterday and lost power to the rear wheels. The differential cup on the left was the destroyed piece. The cup on the right is the healthy differential cup. It looks like the gears ate the seats that hold the spider gears in place. Afterwards they ate everything else inside the cup so the spider gears just spun and couldn't put any power to the ground.