GM Genuine Parts Differential Pinion Bearings are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These bearings are tapered roller bearing elements that support and allow the pinion gear to rotate within the axle or final drive housing. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).