1991 Eaton 21065T, Truck Delivery, Axles, Complete Rears, Fits to: GMC C7000 Topkick, (Used) 1991 GMC C7000 Topkick, COMPLETE REAR DIFFERENTIAL- Part Number: 15566578, Serial Number: H902638136, Make: Eaton, Model: 21065T, Ratio: 4.11, Capacity: 21,000 Lbs, Hub Bolts: 5, Brake Type: Drum, For more information about this item, give us a call. We ship Worldwide! (CRG HEAVY TRUCK PARTS) 929 W PULASKI HWY ELKTON, MD 21921, Ratio 4.11, Serial# H902638136, Casting# H902638136 1GDM7H1J3MJ503259