MoparPartsGiant.com offers the wholesale prices for genuine 2013 Ram 2500 parts. Parts like A/C & Heater Unit 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 5.7L. Transmission: 6-Speed Automatic Transmission, 6-Speed Manual Transmission.