This is the pump driven from the engine not the belt drive coolant
pump. Cummins now charges $645 for a new one - pick up a used one
cheap on eBay starting tomorrow afternoon - search for "131-0267"

These are hard to find and really useful as spares.

Sorry to break "the rules" and put it here - I know no for sale stuff
in the NG - but this is the group of people who could use one.