The Chicago Tribune is reporting that Navistar is now accusing Ford of essentially ripping off a design that the two companies developed in association with each other in a European joint-venture. The company has filed a lawsuit against the automaker over the allegations.

The so-called "Project Lion" was a design for a smaller-displacement diesel V-8 that would go into Ford half-ton trucks and SUVs. Navistar is contending that Ford is moving ahead with the project internally, but using design and engineering recommendations made by Navistar engineers who were consultants on the project.

Navistar is seeking up to $2 billion in damages if Ford breaches its contract with the diesel engine manufacturer before the original 2012 contract expiration.

Diesel Power's Take: Ford and Navistar seems to be the diesel drama of the last few years, and we probably haven't seen the end of it yet.