MoparPartsGiant.com offers the wholesale prices for genuine 2015 Ram 5500 parts. Parts like Front Axle Assembly are shipped directly from authorized Mopar dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 6.7L Diesel, 8 Cyl 6.4L. Transmission: 6-Speed Automatic Transmission, 6-Speed Manual Transmission.