Attention 2004 Model Year Owners: to ensure that you have a 2004.5 Dodge Cummins "600" 5.9L Diesel you must check the engine tag or build date. The engine tag will be located on the front engine cover or valve cover. It will display a rating of 325 HP. Otherwise; you can check the build date which is located in the driver’s side door jamb. If the truck was built in 04 it will be a 2004.5 “ 600” Series. If it does not you most likely have a 2004 Dodge Cummins 5.9L Diesel.