General Motors has moved to fill a market gap with a new 159-inch wheelbase version of the G-Vans, the 4500 Chevrolet Express and GMC Savana, specially developed for the needs of this market. The new chassis will be launched as a 2009-model.

The cutaway van market consists of about 90,000 units, 40% of which fall into Class 4 with GVW ratings of 14,000-16,000 lbs. A little more than half the market is commercial vehicles used for emergency vehicles, airport/hotel shuttles, and student transportation/buses. Other commercial applications include those that require additional GVW and/or heavy duty performance specifications.

The new Class 4 GM cutaway vans provide a high payload capacity and GCW rating, a choice of gasoline or diesel power, and three commercial applications from one chassis, a robust cab design to handle the HD duty cycle, and a 5-year/100,000 mile powertrain warranty.

Most of these vehicles are marketed through specialty vehicle manufacturers (SVMs), who serve as the conduit between GM and end users. They are specially qualified to discuss product features, capabilities, and specifications, provide product comparisons, and recommend specifications.

Two Engines Available 

Two engines are available for this chassis, the Duramax 6.6L V-8 diesel and the 6.0L Vortec gasoline engine.

The 6.6L Duramax diesel was updated for the 2007 model-year to meet new stringent federal emissions standards. The 6.0L Vortec includes variable valve timing and offers a 323 BHP output.

Greg Bilski, GM product manager for full-size vans, noted the transmission in the new 4500 cutaway chassis is a GM heavy-duty transmission, not an Allison. "The reason we can’t use the Allison is that it physically doesn’t fit in this application."

He added that for these uses, the chassis is fitted with a 57-gallon rear-mounted fuel tank, providing the range and weight distribution ambulance and shuttlebus markets need. Axle load ratings are 4,600 lbs. front and 9,450 lbs. rear, with dual rear wheels.

Chassis GVWR Increased

A number of chassis changes were required on the chassis to increase the GVWR from 12,300 lbs. to 14,200 lbs. These changes include:

• Added frame assembly reinforcements.

• A high-capacity rear spring assembly and upgraded rear spring hanger bolt attachments and front ball-joint material.

• Retuned front shock absorbers and revalved rear shock absorbers.

Powertrain modifications included a higher-capacity engine cooling radiator, separate transmission fluid cooler, and the heavy-duty GM transmission. The rear axle was upgraded with reinforced housing, gears and tubes, stabilizer bar assembly, and upgraded parking brake system.

The body structure has been upgraded to meet the HD commercial cutaway duty cycle. Inner fender panels, the body outrigger, and the lower tie bar have been improved to meet the HD duty cycle.

This new 4500 Express and Savana will provide customers higher payload at a lower GVWR than the competition, said Bilski.