This article briefly explains the PACCAR/CUMMINS relationship that we run into with customer’s not knowing the difference between the PX series CUMMINS engines (PACCAR branding) and the true MX series PACCAR engines. Please take a few minutes to look at this so you can better articulate this relationship to the customers.
This explains why some customers have issues connecting to "PACCAR." Reason being is that, essentially, it is a CUMMINS engine with PACCAR branding however, everything else about the engine is truly a CUMMINS (ECU, etc.).
THE LINK TO THE ARTICLE IS BELOW: