Valve, Cascade Overflow: Description: Description
WARNING: This page is about a different car, the 2015 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.
The Cascade Overflow Valve houses a filter screen (4) for filtering the incoming diesel fuel to the fuel injection pump. If the filter starts to get restricted or one of the orifices (2) gets plugged, it will effect fuel flow volume.