BRANSON, MO - General Motors Corp. is tired of having its lunch eaten by Ford Motor Co. and DaimlerChrysler Corp. in the heavy-duty pickup market - and with an all-new '01 lineup of Chevrolet Silverados and GMC Sierras intends to get its rivals to regurgitate some of that precious, high-profit market share.

Heavy duty pickups - those three-quarter-ton and 1-ton jobs, often with dual rear wheels and once used strictly for commercial use - may not be for everyday commuters, but it's a fiercely combative segment where buyers are intensely loyal, and the booming economy has created unprecedented demand.

And as you might have surmised, the economy means this segment now gets its fair share of non-commercial buyers, too, often mixing their duty between work and play, says John Farris, Silverado assistant brand manager. It's the carpenter's work truck during the week and it hauls the boat on the weekend.

Terry J. Woychoski, chief engineer for the heavy-duty versions of the Sierra/Silverado, cuts right to the chase for the all-new '01 models: "We think it's the finest truck we've ever made. We will not rest until we dominate the full-size light truck market."

A hefty order considering Ford's heavy duty F-Series is immensely popular and DC's big Ram is no piker, either. Both have stolen market share from GM, for two reasons. The first is that they're more modern and better-styled than GM's outgoing big pickups.

The second reason is more crucial: They both have better diesel engines. That, says Mr. Farris, is life or death with buyers who demand serious, workmanlike engine torque - and several-hundred-thousand-mile durability.

Knowing that a new diesel was the linchpin, GM, with affiliate Izuzu Motors Corp., aimed to design a butt-kicker - one that despite the ferocious brand loyalty of heavy truck buyers would force the Ford and DC faithful to check out GM's bait.

That all-new diesel is the Duramax 6600 V-8 (see WAW - May, '00, p.137), 6.6 turbocharged liters of common-rail, direct-injected 4-valve-per-cylinder nightmare for Ford and DC.

Forget brand loyalty. Mr. Farris says the Duramax's "sheer numbers" versus the power and torque figures of Ford and Dodge's turbodiesels (7.3L V-8 and 5.9L I-6, respectively), will have rival owners selling their Fords and Dodges and running like Pavlov's dogs to GM.

Sometimes numbers lie, but in this case, they don't (see chart). GM set us up with each maker's turbodiesel truck, hauling an identical massive load of 9,000 lbs. (4,100 kg) in drag races up one of the Ozarks' typical "widowmaker"-type hills. It's a short but steep grade, and by the time the third-mile hill is crested, the Duramax-motivated truck has pulled away from the Ford and Dodge by 100 yards. Up a serious mountain, this could translate to several minutes of less patience-testing towing.

Along with the Duramax are two new gasoline engines: the all-new, 340-hp Vortec 8100 V-8 (replacing the old, old, 7.4L V-8 and more powerful by a good measure than Ford's and Dodge's V-10s) and the Vortec 6000, now making a righteous 300 hp.

There's also a glorious new transmission made by Allison, a smooth yet brawny 5-speed automatic that handles even the prodigious torque of the Duramax (anybody see an irony that the first GM vehicle to get a 5-speed automatic is a jumbo pickup?). GM expects 90% of buyers to go with Allison.

The other available tranny is a neat 6-speed manual made by Germany's ZF. It too, must be a hulking beast to deal with 520 lb.-ft. (705 Nm) of torque.

There's the usual unfathomable plethora of available body and chassis configurations, which, frankly, becomes a bit of a bore, so just remember that GM's new 2500HD/3500-series pickups are based on the already acclaimed GMT800 light-duty architecture, right down to the partially hydroformed chassis, which permits unheralded levels of dimensional control.

Another significant first for GM big trucks is the addition of 4-wheel disc brakes (with antilock control).

These trucks - and powertrains - are outstanding, so it's hard to scoff at GM's reckoning that it can sell an additional 250,000 heavy duty pickups in the '01 model year. GM marketers expect the segment to grow measurably, but a lot of that big number has to come straight out of the hides of its cross-town rivals.