Helps ensure differential fluid does not leak out of your vehicle's differential Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE) GM Genuine Parts are designed, engineered and tested to rigorous standards, and are backed by General Motors GM Engineers design and validate OE parts specifically for your Chevrolet, Buick, GMC, or Cadillac vehicle GM regularly updates production and service part designs to integrate new materials and technologies