GM excited about new medium-duty crew cabs

May 1, 2003
GENERAL MOTORS believes its new medium-duty crew cab line Chevrolet Kodiak and GMC TopKick will offer a truck for every budget and purpose. They are available

GENERAL MOTORS believes its new medium-duty crew cab line — Chevrolet Kodiak and GMC TopKick — will offer a truck for every budget and purpose.

They are available in gross vehicle weight ratings (GVWRs) from 16,500 to 61,000 lb, a broad selection of wheelbases, a range of powerful gasoline or diesel engines, and a variety of automatic and manual transmissions.

“It's the first time General Motors has brought a crew cab factory-built into the medium-duty marketplace,” said Mike Eaves, assistant brand manager-product for medium-duty commercial vehicles, at GM's Work Truck Show presentation.

The other significant news came from marketing product manager Tim Cavanaugh, who introduced the new mid-size Chevrolet Colorado and GMC Canyon trucks. They are all-new pickups designed from the ground up to give consumers more power and space, greater functionality, and a comprehensive range of choices.

Full-length steps and wide doors, front and rear, make cab access easy at all positions.

New cabs provide more room and outstanding comfort and functionality by blending the operator-friendly feel and easy-to-use controls of light-duty trucks with the functionality of a true medium-duty design.

The cabs feature a 50% reduction in noise, vibration and harshness (NVH). Powerful climate-control systems keep occupants comfortable in all operating conditions. A range of high-quality Delco audio systems and amenities like large cup holders provide additional comfort and convenience.

Air bags

Available driver and passenger-side frontal air bags enhance safety. The center of the uniquely designed instrument panel (IP) curves out and angles towards the driver, providing a direct view of controls and gauges with a slight turn of the head. The IP also features up to 24 telltale warning lights and gauges and places them within closer view and easier reach of the driver for added safety. A rear-window defogger to improve rear visibility is another option on the crew cab.

Crew cabs provide highly flexible storage, including a fold-down rear seat and available seat-delete options. The front passenger seat and rear seat on crew cabs can be deleted to support specific customer needs. The entire two-passenger front seat lower cushion can also be lifted to provide a large storage container. An available floor storage tray is located at the back of the cab and there are storage pockets in both sides of the front doors. Additional storage compartments with hinged doors are available in the front and rear step wells.

Additional functionality comes from two 12-volt power points on the instrument panel, along with an available cigarette lighter in the center console.

Low step-in heights, generously sized tread plates, and convenient assist handles also provide easy vehicle entry and egress. C4500/C5500 models, for example, facilitate entry with two evenly spaced 36" steps. Rear doors on the crew cab open to an exceptionally wide 70 degrees for easy entry and exit.

Parked cars and misplaced trash containers are less of an obstacle for the Kodiak and TopKick because longer front suspension springs and a set-back front axle provide superior maneuverability.

The wider front track of the Kodiak/TopKick permits a 53-degree wheel cut and greater stability, allowing a turning diameter as low as 47'.

Increased visibility

Another major factor contributing to safety and cost-savings is increased visibility. GM says visibility in the Kodiak/TopKick is best in class, thanks to an aerodynamic sloping hood design, a windshield that is 40% larger in area, and new convex outside rearview mirrors that are larger than the old door-mounted mirrors. The state-of-the-art exterior mirrors, attached to the body-side cowl to greatly reduce vibration during operation, can fold forward and backward making them less prone to damage.

The net result is the ability to see objects on the ground as close as 13.8' in front of the truck (as measured from the front bumper), which gives a 13' sight advantage over comparable competitive models (with their average of 26.8'). GM says that's even better than the forward visibility measurements of many compact pickup trucks.

The Kodiak/TopKick C4500-C5500 Series (Class 4-5) includes regular and commercial cutaway chassis cabs, and vocational packages to cover School Bus, Fire and Rescue, Ambulance, Shuttle Bus, Wrecker, and Snowplow requirements. Gross Vehicle Weight Ratings (GVWRs)ranging from 16,000 to 17,500 lbs for the C4500, and from 18,000 to 19,500 lb for the C5500, make it easy to find the perfect offering to get the job done right.

For even bigger tasks, the new Kodiak/TopKick C6500, C7500 and C8500 Series (Class 6-7-8) trucks offer regular and commercial cutaway chassis cab offerings along with the crew cab. This model range also includes LoPro (low profile) and tandem axle variants.

The Kodiak/TopKick vehicle architecture shares a stamped, straight section, C-channel frame design, providing maximum strength and a clean back-of-cab design for easy, low-cost body and equipment installations.

Frame strengths

By using three variations of frame strength, GM's Class 4-5 models optimize weight- and load-carrying capability for their specific applications, without requiring any reinforcement.

Variations include: 6 mm-thick frame rails with 50,000-psi strength steel for bus and motor home chassis, providing a 381,500-lb-inch resistant bending moment (RBM); 6 mm-thick rails with 80,000-psi strength steel for select conventional cab models and all commercial cutaway cab chassis, providing an even more impressive 610,400-lb RBM; and 8 mm-thick rails with 80,000 psi-strength steel for crew cab and long wheelbase conventional cab chassis models, with an astounding 824,800-lb RBM.

The C4500/C5500's stronger, longer frames provide wheelbases ranging up to 235", with plenty of rear overhang for upfitter applications. Fuel tanks, available in four different capacities, are mounted cleanly between the frame rails. They include 25-, 40-, and 60-gallon single tanks and 40-gallon capacity, provided by dual tanks.

C6500/C7500/C8500 models also use larger-sized frames and offer a wider selection of wheelbases and single and tandem rear axle configurations to accommodate larger-sized bodies. Single-axle models can easily accommodate bodies up to 30' in length, without requiring any extra-cost frame extensions.

C4500-C7500 models (with up to 33,000-lb GVWR) feature a new standard hydraulic four-wheel anti-lock disc brake system, with standard four-channel ABS, Electronic Brake Distribution and available traction control.

C4500 models with the lightest front axle utilize low-drag, twin-piston calipers on the front and rear brakes. C4500 and C5500 with the 7,000-pound front axle have an extra high capacity, four-piston caliper front/twin-piston rear design. Brakes on wrecker models are both load- and application-specific. C4500/C5500 models also feature a common, larger-sized 381 mm × 38 mm rotor, which reduces heat and enhances brake life.

C6500-C8500 models have a low-drag, four-piston opposed piston, fixed caliper brake design, with diameters sized to particular GVW/load requirements. Premium, high-capacity, 70 mm, four-piston brake systems are now standard on both the front and rear.

Twin-piston brakes feature a new pin-sliding design. Heavier models, rated at 19,500-lb GVWR and up, feature a new “totally fixed mount” caliper design. Both brake designs reduce wear, corrosion, and potential caliper binding by separating the function of moving the caliper from that of applying actual clamping force to stop the truck. The new non-asbestos brake linings last up to twice as long.

Crew cab models feature the HydroMax brake booster for brake actuation. Both HydroMax and HydroBoost (used on some conventional cab vehicles) operate on the same principle, with the power steering pump supplying the booster power. A tandem (split) master cylinder provides the independent front and rear circuits for the hydraulic brake system. Sensors warn the driver of “low fluid” or secondary brake failure.


The all-new 2004 Colorado marks the fifth all-new Chevy Truck since the announcement of the Chevy Avalanche at the 1999 North American International Auto Show. Colorado and Canyon production will begin at the General Motors Shreveport truck plant in Shreveport, Louisiana, in the fourth quarter of 2003.

The trucks cover the segment with nine model configurations, including three suspension packages (standard, sport, and off-road), three cab styles (crew, extended, and regular) and two- or four-wheel drive.

They feature new inline five-cylinder and four-cylinder engines that will provide the power of a V-6 and the efficiency of an I-4. The Vortec 3500 and Vortec 2800 are derivatives of the award-winning Vortec 4200 six-cylinder engine featured in the TrailBlazer and TrailBlazer EXT.

With their common design, the new I-5 and I-4 engines feature the same all-aluminum construction, dual overhead camshafts, and four-valves-per-cylinder technology as the Vortec 4200. The new engines also share the I-6's high 10:1 compression ratio, electronic throttle control, exhaust cam phasing, coil-on-plug ignition, direct-mount accessories, and easy maintenance features.

The cast aluminum four- and five-cylinder engine blocks and aluminum cylinder heads are produced using the same lost foam casting process as the Vortec 4200. This process allows more exact dimensional control while reducing machining efforts in oil galleries, coolant, and other internal passages.

Overall, the new engines share 75% of their components with Vortec 4200 and 89% of their components with each other. This provides customers with highly proven design features and enables GM to develop and introduce them more quickly and at a lower cost.

About the Author

Rick Weber | Associate Editor

Rick Weber has been an associate editor for Trailer/Body Builders since February 2000. A national award-winning sportswriter, he covered the Miami Dolphins for the Fort Myers News-Press following service with publications in California and Australia. He is a graduate of Penn State University.