2012 Meritor/Rockwell RP23-160, Truck Tractor, Front Rears (Tandem Front), Fits to: Western Star 4900 SA, (Used) 2012 Western Star 4900 SA, COMPLETE FRONT DIFFERENTIAL GEARS ONLY- Part Number: 33063A7051G3.91, Serial Number: FOR01693784, Make: Meritor/Rockwell, Model: RP23160NCN1806 391, Ratio: 3.91, Capacity: 23,000 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 3.91, Serial# FOR01693784, Casting# FOR01693784 5KJJALDR8CPBN4842