WESTLAKE VILLAGE, Calif. — In their respective segments, Caterpillar and Cummins rank highest in satisfying customers with heavy-duty truck engines and transmissions, according to the J.D. Power and Associates 2007 Heavy-Duty Truck Engine/Transmission Study released this week.

The study, now in its 11th year, measures customer satisfaction with engines in two-year-old heavy-duty trucks (Class 8) by examining four vital engine factors. They are (in order of importance): engine quality (30%); engine performance (26%); engine cost of ownership (22%); and engine warranty (22%).

Cummins ranks highest in customer satisfaction in the heavy engine vocational segment with an overall index score of 750 on a 1,000-point scale. Cummins performs particularly well in the engine warranty, engine performance and cost of ownership factors, according to the study. Caterpillar closely follows Cummins in the segment with a score of 747, performing particularly well in engine quality.

Caterpillar ranks highest in customer satisfaction in the heavy engine pickup and delivery segment with an index score of 754, performing well across each of the four engine factors. Caterpillar performs particularly well in the engine quality and engine performance factors, the study says.

The study is based on the responses of 2,677 primary maintainers of two-year-old heavy-duty trucks.