Customer satisfaction for owners of Class 8 trucks has declined from 2004, according to a new report from J.D. Power and Associates.

According to the survey, overall customer satisfaction with heavy trucks has declined in the last year, with general quality and engine performance leading the complaints. The satisfaction scores were based on six different factors, including the previously mentioned quality and engine performance; exterior; ride, handling and braking; transmission; and interior.

Kenworth came out as the top-ranking company in the over-the-road segment. The firm surveyed nearly 2,500 drivers and maintainers of Class 8 trucks, with Kenworth taking the lead in three areas, including quality, engine and sleeper factors.

The survey cites complaints about fuel economy – which dropped below 6 mpg for the first time in the 10 years the survey has been done.