Recently acquired a 1998 Dodge Ram 1500 and wanted to start all maintenance from square one because I don't know its history. Today I changed the rear differential fluid, and found these little guys stuck to the magnet at the bottom of the case (penny included for scale). The guts of the diff looked fine, so I'm confused as to where they came from. I've driven it nearly 2000 miles since I got it, and it drives just fine. Any one know what they are?