In a lawsuit filed in Chicago, Navistar accused Ford of breaching a 2002 contract to produce a 3.6-liter diesel engine known as the Lion V-8, Crain's Chicago Business reported.

Navistar says it spent $11 million designing the engine that was to have been built in Europe and used overseas before Ford lost interest.

The lawsuit claims Ford plans to build its own version of the Lion V-8 in Mexico.

Ford said the claims were "entirely without merit."