It's really impossible to overstate the importance of General Motors Corp.'s new GMT800 program.

North American market share, executive bonuses, production workers' profit sharing checks, advertising revenue for every major television network well as the heaviest hitters in magazine publishing all depend on how well GM competes in the lucrative trench warfare of full-size pickup trucks and sport/utility vehicles.

This investment, which analysts estimate will approach $6 billion by 2000, represents GM's attempt to regain its long-held dominance in the segment. It also provides the engineering and manufacturing foundation for the next generation Chevrolet Tahoe, GMC Denali, Suburban and Cadillac's yet-to-be-named fullsize SUV (the initial version will be based on the old C/K truck platform).

We're talking about 1.2 million, or 25%, of the 4.73 million light vehicles GM sold in the U.S. last year, and the most profitable ones at that.

"This is the mother of all programs, not only to GM, but to suppliers as well," says Michael Robinet of CSM Corp., an industry forecasting and consulting firm in Lansing, MI. "If a supplier latches on to this program, the volumes are huge, and they are all concentrated in North America. Consequently, some suppliers are willing to take lower profit margins on this business because the volumes are so huge."

Although full-size pickup sales declined slightly in 1997, the annual growth rate has exceeded 10% in three of the last five years.

This is the first re-engineering of the company's basic pickup and large SUV platform in a decade. There are new body shops in three assembly plants: Oshawa, Ont.; Pontiac, MI, and Fort Wayne, IN. By the time the sport-ute rollouts are completed, up to 10 assembly plants will have been retooled, spanning the U.S., Canada, Mexico, Brazil and Argentina.

Common manufacturing processes, an average parts count of 200 (down about 10% from the current generation C/K pickups), and buying parts from suppliers involved in other global GM vehicle programs hold the potential for an even bigger payoff if sales targets are met.

Indeed, there's lost ground to be recaptured. The huge success of Chrysler Corp's boldly styled Dodge Ram and Ford's curvy F-series took a toll on the General. From 1990 through 1993 GM consistently held 51% of the big pickup market. That slipped precipitously to 37% in 1996 before rebounding to about 40% last year. For two consecutive years Ford Motor Co.'s F-series pickup truck has outsold Chevrolet's C/K and GMC Sierra combined.

On the surface, it appears GM Vice President and Vehicle Line Executive Michael Grimaldi and crew have played it safe. Chevrolet, which has chosen the Silverado nameplate to replace the generic C/K designation, has gone with an evolutionary design. GMC's Sierra features a more prominently proud grille to better establish itself as the distinctively up-market choice.

"I think a lot of people have forgotten how radical a change we made when we introduced the current truck in 1988," says Ed Schoener, assistant brand manager for the Silverado. "This is just another step. I would expect that Dodge, when they iterate to their next generation of the Ram, will not turn to a completely out-of-the-box perspective."

Beauty, at least as measured by GM's market research, is more than skin deep for truck buyers. Consequently, GM has put more mechanics before cosmetics.

There are three all new versions of its Vortec iron-block V-8 - a 4.8L, a 5.3L and a brawny 6L that cranks out 300 hp, the kind of oomph that could haul a freighter up Pike's Peak.

Sure they still rely on push-rod technology as opposed to the competition's overhead-cam approach, but the horsepower will exceed Ford's and Dodge's at every level.

"The customer is buying power, not technology," says Kenneth Sohocki, chief engineer for GMT800. "If we can provide that at a lower cost (the push-rod design is saving about $100 per engine) we will do it. There's also the inherent low-end torque advantage you get with push-rod technology."

These will be the industry's first full-size pickups on which four-wheel disc brakes are standard.

Then there's the hydroforming technology used to fabricate the front frame rails and engine cross members (see story p.47). Magna Inter-national's Cosma Div. wrestled this job away from such industry heavyweights as Dana Corp. and Tower Automotive. Hydroforming uses water or other fluids under very high pressure to precisely shape metal tubes into hollow structures. It reduces weight because there are no welds, which saves on labor and machining costs.

While it has been used on certain niche vehicles, this is the first time hydroforming has been used on a high-volume vehicle involving the kind of weight of these hefty V-8 engines.

To understand how these trucks evolved, it's necessary to remember what was happening in the 1991-'92 timeframe.

True, there were soon to be changes in the way competing trucks looked. But nobody foresaw that the full-size pickup market would nearly double from 1 million units a year in 1991 to more than 1.85 million in 1996.

Both Chevrolet and GMC were conducting focus groups, but at that point the Dodge Ram was not yet on the market.

"We knew Toyota was coming to market with packaging sizes that were a little smaller," says Chevy's Mr. Schoener. "But we were hearing from our customers that they wanted something a little bigger."

So GM truck engineers mustered together five different test bucks made out of wood and styrofoam, and outfitted them with a windshield and seats. Two were smaller than the existing C/K, one was the same size and two were larger. Then they invited existing GM truck owners to sit in them and say what they liked or disliked.

"It came as a shock that most of them found our existing truck too small," says Mr. Schoener.

Indeed, three years later, it was obvious that Toyota's in-between approach missed the market. But Dodge, and later Ford, discovered the bigger-is-better trend and adapted their trucks accordingly.

>From the outset, product planners spent more time probing prospective buyers' opinions about what they experienced in driving the truck than what they thought about its looks.

Prototypes were equipped with switches and control modules through which the development team could vary torque curves and horsepower. They also could adjust the throttle response to see whether focus groups preferred a lot of power from a slight tapping on the accelerator or a more gradual response.

"We not only ran tests with customers doing normal driving, we made them go through parking situations and trailer towing," Mr. Schoener says. "Then we measured what they liked and changed certain performance elements according to their feedback. Before, when we used to do throttle progressions, the final decision was just a golden gut call by the engineering staff."

Then why won't the extended cab Silverado and Sierra have four doors? Dodge and Ford will offer that feature before the first '99 GM offerings reach the showroom.

"When you do a new platform this large you just don't change everything all at once," says Mr. Grimaldi. "I won't give you the specific date, but there will be a fourth door."

For the time being, space-hungry truck buyers will have to settle for a third door on the passenger side. Advertising will tout the additional 1.1 ins. (2.8 cm) of rear-seat legroom (29.8 in./75.7 cm vs. 28.7 in./72.9 cm) in the '98 C/K pickups. At the North American International Auto Show, GMC illustrated the point by putting 6'5" Richard Wagoner, GM president of North American Operations, in the back seat of its SierraAce concept truck.

The biggest challenge for GM will be to translate the streamlined processes achieved in the pilot stage to the factory floor. By setting up a replica of the assembly line at its $103 million Validation Center within the walls of the old Pontiac West assembly plant, the GMT800 team has tried to familiarize workers with the faster, leaner ways the new truck will come together.

While Mr. Grimaldi declines to discuss how many fewer workers will be needed, that very contentious issue was at the heart of last summer's three-month strike by the United Auto Workers union at the Pontiac East plant. The strike caused management to shift the initial launch for the new trucks to Oshawa, Ont., near Toronto.

Mr. Grimaldi and Chevrolet General Manager John Middlebrook both acknowledge that GM's big pickup sales will fall this year as the changeover begins in Oshawa in July, Pontiac in September and Fort Wayne later this fall.

Production of the next generation of large SUVs will begin in the summer of 1999 at Silao, Mexico, followed by Janesville, WI, and Flint, MI, in the fall of next year.

Mr. Grimaldi and other GM executives adamantly deny that the program is behind schedule, but he does not dispute supplier reports that the number of engineering changes has been substantial. He even boasts that there have been more than 2,000 changes in the manufacturing process from the beginning.

"That's been our plan," he says. "You make changes up front before you put tools in the assembly plant and push the button for Job 1. As a result we're predicting far fewer problems in the production startup stage."

Despite the drive for common parts and processes, there still are at least 40 different configurations of cab size, body style and drivetrain.

Says Kurt L. Ritter, brand manager for Silverado and the man responsible for bringing both Bob (Like a Rock) Seger and Cal Ripken into Chevy's marketing arsenal: "At least we're getting close to the point where we can count them."

The GMT800 may be a ground breaking project for General Motors Corp. because of its enormous size, but suppliers involved also have come to find it revolutionary in their own way.

GM invited suppliers to take an active role from the beginning of the project, allowing them to lend their engineering and design expertise throughout development. In past product development cycles, suppliers were more likely to take orders from the top, without having much input.

The result is a "seamless team" that allows suppliers to sit in on conference calls and participate in project teams targeting various challenges associated with GMT800.

"They have moved considerably in integrating the suppliers early on, not just Tier 1 but also Tier 2 suppliers," says Marcie Kurcz, business development manager for GM Truck at GE Plastics.

The Southfield, MI, company contributes the resins for 50 lbs. (22.7 kg) of plastic components on the vehicle, including mirrors, beltline moldings, underbody shields and grille. The parts are made from weatherable polymers and require no painting.

Along with an increased role for suppliers comes a greater responsibility for design and engineering work.

"This is work you wouldn't have seen 10 years ago because it was all done by GM. Now they're pushing it out to the tiers," says Dave Von Behren, director of the OEM team at GE Plastics. "It forces a tight relationship because you're intimate with these parts from early on."

The result, says Mr. Von Behren, is better quality. "Now we can pay more attention to tooling and design," he says.

Michael Grimaldi, GM's vehicle line executive overseeing the GMT800, says that suppliers were made aware early on how important their role was to the success of the launch. "We told our suppliers, 'You're part of this team. Together we will succeed,'" he says.

"We all understand that to minimize quality problems, we've got to work with suppliers up front. We're doing it on all our car and truck programs,"Mr. Grimaldi says. "The requirement was to have the best-in-segment reliability, and the suppliers know this. They all understand the quality requirement."

A key element in tracking supplier quality is GM's Validation Center in Pontiac, MI, where pre-production models are built at line speed and thoroughly tested so problems can be quickly addressed.

"We are tracking it as we speak," Mr. Grimaldi said during the North American International Auto Show in Detroit, where the new Silverado and Sierra pickups were unveiled.

Ms. Kurcz says from personal experience the tracking method works well and involves weekly meetings in which suppliers participate. "Accountability has been improved," she says. "Problems are being resolved early on, and things don't fall through the cracks. There's a lot of brainstorming that goes on."

She says her company has been working on the GMT800 for five years, and one of the earliest projects involved developing the thermoplastic door handles.

For some truck buyers, door handles had to be chrome. But with the broader mix of people buying trucks these days, Ms. Kurcz says market research found that matte finish thermoplastic handles would do quite nicely, especially if they kept the cost down.

A number of painted metal parts also have been replaced on the GMT800 with molded-in-color thermoplastic. Eliminating painting cuts costs by between 30% and 50%, she says, not to mention the environmental hazards of paint plant emissions.

Once upon a time only engineers cared about vehicle frames. Now they're trotted out at auto shows and displayed like fancy new models. Mercedes-Benz AG really got the ball rolling last year by introducing only the chassis of its new M-class sport/utility vehicle at the North American International Auto Show in Detroit - and saving the introduction of the whole vehicle for later. Chrysler Corp. followed suit last month at the NAIAS by showing the underpinnings of its yet-to-be-introduced 1999 Jeep Grand Cherokee.

Some critics may consider this a bit over-the-top, but many others say it's about time automakers give chassis and frames their due. They are the foundation upon which a vehicle's quality, safety and handling characteristics are built, so why not show them off?

Big strong frames are especially important to trucks, so it should come as no surprise that General Motors Corp. spends lots of time talking about the redesigned frames on its new GMT 800 full-size pickups during an introductory press conference late last fall (see WAW - Dec. '97, p.85) and during the formal introduction at NAIAS in January.

As you would expect, the new frames - which eventually will be used to carry versions of Chevy and GMC Suburban, Tahoe and Yukon sport/utility vehicles in addition to full-size pickups - are substantially lighter, stronger and stiffer than their predecessors.

New tubular cross members provide improved torsional performance over traditional stampings, and welded construction is used in place of rivets in many areas. A rear lower control arm cross brace adds additional support. The frames also are built in three modules, allowing the front, mid and rear sections to be produced independently, using materials and processes that allow the three sections to meet specific performance requirements without adding too much weight.

But the new GM frames are especially significant because they represent the first use of hydroformed front frame rails in a very high-volume automotive application. Hydroforming is a process that uses water or other fluids under very high pressure to expand metal tubes inserted into die sets and shape them into hollow structures.

The process has been used in the aerospace and other industries for decades, but has caught on only recently for structural applications in automotive. In the structural arena, hydroformed tubes are being used to replace box section assemblies typically made of stamped steel components welded together, such as the frame rails. Thenew Chevrolet Corvette uses hydroformed components extensively in its frame, and the new Chrysler LH cars use hydroformed engine cradles. Proponents claim the process is ideal for making car subframes, engine cradles, radiator surrounds and supports, lower and upper longitudinal body rails, D-pillars for station wagons and various body crossmembers.

"We feel the market for this technology is enormous. It could change the metal-forming business forever. It's that significant," says John Thomas, director of sales and marketing for the Cosma Div. of Magna International Inc., the frame's supplier.

GM also credits the hydroformed front rails with enabling the frame to absorb 35% more crash energy. The hy-droformed "crush caps" deliver excellent front-end crush performance and reduce repair costs in many accidents because they can easily be replaced if damaged in low-speed impacts, GM says.

Magna won the frame contract - reportedly worth $370 million - several years ago, based on its proposal to use hydroforming extensively in the design.

Proponents say hydroforming lowers assembly and tooling costs and cuts die wear while reducing weight and increasing strength and stiffness. Based on some estimates, hydroformed steel parts are 10% to 15% lighter than comparable stamped steel assemblies. Industry analysts have estimated that GM's new truck frames could weigh 25 lbs. (11 kg) less and be $60 cheaper than their predecessors thanks to hydroforming.

Cosma's Mr. Thomas diplomatically avoids confirming those numbers by saying the new frame incorporates many new components - including front axle bushings, tow hooks, exhaust hangers, weld-nuts, front bumper brackets, front and rear jounce bumpers, torsion bar isolators and the park brake bracket - which the previous frames did not.