the cummins parts book lists it as :cover breather,crankcase.. on my engine it is option BR9284, you can call the nearest cummins parts guy and give him your engine serial number and CPL number and they can tell you everything about your engine and what it came with when built. (most engines will have a white decal with black lettering with the engine serial number and CPL number on it.... it is located on the top of the valve cover at the back of the engine, to find it look at the center of the fire wall of the truck, then look down on top of valve cover near the fire wall to see it) once you have those numbers you can even go online to cummins quickserve and find things specificaly for your engine. a local dodge dealer will be able to get one in their parts system as well, hope this helps with your search some.