I was just changing the diff oil on my 2003 Disco 2. When I pulled the rear drain plug, the oil had a metallic sheen to it and a lot of fine particles on the magnet - way more than the front or what I’m used to seeing. When I felt through the particles I found these bits in the picture. How worried should I be? I’ve bought the vehicle at 82,000 miles and have just under 86,000 on it now.