Give Cummins your engine serial number found on the data tag on the gear housing, without it they are completely lost.
With the esn the Cummins parts jockey should be able to see a list of every part on your truck's engine (that Cummins supplied).
If you were to buy a new truck it might take them 6 mos. to a year to get that esn in the software sent out to the Cummins Dist. /dealers.
Good luck,
Andy