DETROIT — Citing a contractual dispute with one of its engine suppliers, Ford Motor Co. stopped taking orders on Feb. 7 for its 2007 model year E-350 and E-450 chassis with 6.0-liter diesel engines. These chassis are used as platforms for Type A school buses, as well as ambulances, shuttle buses and parcel delivery trucks.

Jerry Renauer, an account specialist in Ford’s Commercial Truck division, said between 4,000 and 5,000 cutaway school buses are built on the E-350 and E-450 chassis each year. About 90 percent of those chassis are equipped with diesel engines; the other 10 percent are gasoline-engine chassis.

Renauer said all of the major school bus manufacturers were notified of the hold, which will continue indefinitely. “Even if they agreed [to an engine contract] today, there would still be some disruption down the road,” he said, explaining that the disputed engine is only one part of the supply chain that will be affected.

To fill in the gaps created by the diesel-engine shortfall, Renauer said, Ford recently released a 10,700 GVWR E-350 chassis that can utilize a 5.4- or 6.8-liter gasoline engine. In addition, for its 2008 model year, Ford’s E-350 will become an 11,500 GVWR with a gasoline engine beginning Aug. 1.

Renauer said a 14,500 GVWR E-450 with a gasoline engine could also be available Aug. 1. He said it’s currently being built by Thomas Built Buses for crash-testing by Ford.

With Ford putting its diesel chassis on hold until further notice, GM stands to inherit much of its cutaway market.

“We’ll be picking up a lot more orders,” said Peter Schmid, GM’s national bus manager. He said GM has products that can be easily substituted for Ford’s E-350 line. But he added that Ford’s 14,050 E-450 chassis is the only one of its size and capacity in the industry and cannot be directly replaced by a GM product.

However, Schmid said GM is developing a 14,050 GVWR chassis for model year 2009 that will be ready for order in April 2008 and for delivery later that summer. It will be powered by the 6.6-liter Duramax diesel engine or the 6.0-liter GM gasoline engine. Both will be school bus certified.

Other alternatives to the E-450 are GM’s 12,300 GVWR chassis, which is smaller than the E-450 and has less capacity, or the C4500 and C5500 medium-duty chassis, which can match the E-450’s capacity. Schmid said customers should take into account that the C4500 and C5500, although more expensive to procure, have lower life-cycle costs than their cutaway counterparts.