Clean the differential case in the solvent and note chips, cracks, injury to bolt holes, rough wear, grooves, scoring, damaged side bearing flanges, heat discoloration, badly-worn differential pin bores. Also clean the ring gear in solvent and check for any damage to the threaded holes and any abnormal wear or heat discoloration of the gear teeth. Use the pinion flange to clean it with solvent, and make inspections for wear, pitting, and splines and grooves or pitting on sealing surface. Examine the bearing rollers and races for pitting, scoring, grooving, extreme wear, and other defect, with heat discoloration that varies from pale yellow to deep blue, which imply overload or insufficient oil; Any heated colored bearings or races must be changed. Further, check for bent bearing cage, and inspect for damaged bearing cage.