1991 Meritor/Rockwell RS15-120, Truck Delivery, Rear Rears (Tandem Rear or Single), Fits to: Ford F600, (Used) 1991 Ford F600, DIFFERENTIAL GEARS ONLY- Serial Number: NKA90061827, Make: Meritor, Model: RS15-120, Ratio: 4.88, Capacity: 14,000 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 4.88, Serial# NKA90061827, Casting# NKA90061827 1FDNK64PXMVA09531