• Beginning next year, Navistar is going to adopt an exhaust-control technology that Cummins uses. Navistar has been paying penalties to the government because its engines cannot meet 2010 nitrogen-oxide emission rules.
• The change to Cummins' selective-catalytic reduction system, which works on the exhaust stream rather than in the engine itself, will be implemented first on Navistar's 13-liter MaxxForce engines.
• Navistar had been using a technology it licensed from the U.S. Environmental Protection Administration – recirculating exhaust gases in the cylinders – but could not achieve federal emission requirements.

From the article:

Navistar International Corp. is abandoning its decade-long Class 8 diesel-truck-engine strategy and turning to rival and onetime supplier Cummins Inc. for a viable solution.