Fiat and Cummins in court

I'm fairly sure that Chrysler and Cummins have worked together on the overall engineering of these trucks for many years. It's not so simple as FCA buying a bunch of Cummins engines and putting them in trucks. The B series engines that Cummins supplies are specifically designed to be used in FCA built trucks, so I can see that both companies have a role in engineering the emission systems used in those trucks.