Auto Service World
Feature   February 1, 2001   by CARS Magazine

GMC W-Series

Serious Inquiries Only


Is towing/recovery a serious part of your business? If so, then choosing a chassis option for that expensive wrecker body is likely to revolve around both cost and productivity, especially given the cost-competitiveness of contract towing. One option is the converted pickup cab-chassis, usually a one-ton dually, often diesel powered. They’re comfortable, look good, and can tow your boat or snowmobiles on the weekend. They’re also expensive, both to buy and operate, and like all conversions, are a compromise. At the other end of the scale are full medium-duty trucks, which are more capable, and are also expensive.

SSGM tested a GMC W4500 cabover diesel with a representative body and hydraulics and found it to be an excellent cross between the advantages of a medium-duty cabover truck and the agility and cost advantages of pickup-based units. The test vehicle was powered by a turbocharged, intercooled 4.75L four-cylinder diesel, which generated 175 horsepower at 2700 RPM and 347 lb./ft of torque at 2000 RPM. Surprisingly, the power fed through a four-speed automatic transmission (with lock-up on second through fourth gears) to a 5.375 rear axle, giving a comfortable 110km/h cruising speed, probably limited more by aerodynamic drag than power. Anti-lock hydraulic brakes were supplemented by an exhaust brake, just like the big rigs, which greatly reduced brake use, especially when loaded. GM estimates that brake life can be as much as doubled by use of the engine brake, which is selectable from the driver’s seat. Front disc brakes are attached to a reverse Elliot beam axle featuring ball-bearing kingpins for extra durability. Suspension is by semi-elliptic leaf springs front and rear, with a sway bay up front.

The cabover design gives outstanding visibility and a tight turning circle and routine maintenance items such as fuel and oil filters as well as dipsticks and fill points are clearly marked and easy to reach. The W-4500 seems to be designed to simplify the driver’s task with a simple dashboard featuring nothing but a speedometer, fuel and temperature gauges, a tilt-telescopic steering wheel and insulated headliner and door panels. With a GVWR of 8142 kg (17,950lbs) and hydraulic brakes, drivers won’t need a special license to operate the vehicle, and technicians won’t find any scary technology in either drivetrain or chassis.

And how does it run? The W-4500 is surprisingly “light-truck” in its agility and performance, although with a recovery body and hydraulics, acceleration and top speed won’t impress if you’re used to passenger car driving. The flip side was an average fuel consumption figure of 14 MPG in real-world mixed city and highway driving, which betters several diesel pickups. The other major plus to the W-Series cab-chassis is price. The test unit optioned with AM/FM stereo, automatic transmission, oil pan heater and upgrade mirrors stickers at almost exactly $41,000, freight included.

The downside? There really isn’t one, although this is most definitely a truck. The ride is firm, and the cab is spartan by high-end pickup standards. One quibble is with the nicely upholstered cloth seats. They’re comfortable, but will probably hold dirt in towing/recovery service. A vinyl covering would be better.

The W-Series is designed for serious work, so don’t expect to haul your Airstream to Florida in one. On the other hand, if you’re serious about generating revenue from your towing/ recovery operations, these cabover chassis are an excellent platform with low costs both at buy in, and in operation. You can always take the money you save and buy a nice pickup. SSGM