2016 Detroit RT40-4N, Truck Tractor, Rear Rears (Tandem Rear or Single), Fits to: Western Star 5700, (Used) 2016 Western Star 5700, COMPLETE REAR DIFFERENTIAL GEARS ONLY- Part Number: C11-00042-503, Serial Number: 771AAC-A178020T, Make: Detroit, Model: RT40-4N, Ratio: 3.08, Capacity: 20,000 Lbs, 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 3.08, Serial# 771AAC-A178020T, Casting# 771AAC-A178020T 5KJJBHD17GLHC8425