All Eaton differentials made for General Motors 8.5" and 8.6" axles require special bearings. For axles with small bearing bores (race O.D. or 2.89"), usually found on vehicles prior to 1999, bearing LM102949 and race LM102911 are required. For axles with large bearing bores (race O.D. of 3.06"), usually found on vehicles from 1999 to present, bearing LM603049 and race LM603012 are required.