New Old Stock (NOS) Genuine Detroit Diesel hydraulic pump coupling, part # 05135378 (also 5135378), for Series 60 engines (11.1L, 12.7L, 14L models) in buses, trucks, and heavy-duty diesel vehicles. Made OEM part is unused, in original packaging with minor shelf wear. Metal parts like gears have grease on them, this is not rust as some pictures my seem to show. HIGH-VALUE / SERIALIZED DIESEL PART? Clear evidence of part swapping or fraud? Honest mistakes or fitment questions? Happy to work it out!