2005 Meritor/Rockwell RD20-145, Truck Tractor, Rear Rears (Tandem Rear or Single), Fits to: Western Star 4900 FA, (Used) 2005 Western Star 4900 FA, COMPLETE REAR DIFFERENTIAL GEARS ONLY- Part Number: 33063A7090A3.73, Serial Number: AV05047760, Make: Meritor/Rockwell, Model: RD20145NFN3572, Ratio: 3.73, Capacity: 20,000 Lbs, Hub Bolts: 10, 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 3.73, Serial# AV05047760, Casting# AV05047760 5KJJAEDE45PV53952