Navistar International Corp. and Cummins Inc. have finalized the agreements necessary to supply the Cummins ISX15 engine for International truck models as well as the inclusion of the Cummins Emission Solutions aftertreatment system to Navistar’s MaxxForce engines.

The ISX15 will be included in the International ProStar+, PayStar and 9900 models, Navistar said. The SCR aftertreatment system will be utilized on MaxxForce big bore engines.

“This agreement represents a natural extension of the long-standing relationship between Navistar and Cummins and our history of collaboration in serving our mutual customers,” said Troy Clarke, Navistar president & COO. “With the addition of the Cummins ISX15 and the use of the proven Cummins aftertreatment system, we are on a clear path to providing customers with proven, reliable and fuel-efficient clean engine technology.”

Navistar will begin its initial builds of the International ProStar+ with the Cummins ISX15 in November with the first customer shipments in December. The International ProStar+ with MaxxForce 13 and the Cummins Emission Solutions SCR-based aftertreatment system will enter initial pilot production in March 2013 with regular production to begin in April 2013.

The remaining line-up of heavy-duty truck models will transition to SCR-based clean engine technology in a phased launch throughout 2013 based on volume and customer demand, Navistar said.