MoparPartsGiant.com offers the wholesale prices for genuine 2021 Ram 1500 parts. Parts like Auxiliary Coolant System are shipped directly from authorized Mopar dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 3.0L Diesel, 6 Cyl 3.6L, 8 Cyl 5.7L, 8 Cyl 6.2L. Transmission: 8-Speed Automatic Transmission.