Chevy ' s Secret Weapon - Sneak Peek

If our extensive inside information is correct, the ' 99 Chevrolet full - size pickups and the year 2000 Tahoe sport / utility based on them promise to be very good indeed.

It ' s been more than a decade since GM revamped its full - size pickup line, which has put the venerable haulers at a disadvantage in overall comfort compared to archrival Ford.
For the Chevy and GMC pickups ' redo in ' 99, the engineering and styling changes will be evolutionary, not revolutionary. But make no mistake, the improvements are more than just small advancements. Look for the new pickups to continue the deli - menu approach to hauling, allowing buyers to choose from a variety of mix - and - match bodystyle, powertrain, and comfort options, with prices ranging from the high teens to over $30, 000. The Tahoe sport / ute promises to be even more luxurious than ever, and available in two - or four - door configurations.

Chevy recently gave Motor Trend a glimpse at what ' s going on with the code - named GMT800 trucks. The public ' s first peek at them occurs about the same time this magazine hits the stands, at the North American International Auto Show in Detroit in early January. Production is due to begin on an undisclosed date this spring with the Tahoe sport / utility build arriving months later. Here ' s what we know from our study of the prototypes at GM ' s truck development center.

For the diverse requirements of individual truck buyers, GM will offer five different OHV engines from a 4. 3 - liter V - 6 to a 6. 5 - liter V - 8 turbodiesel. Three of these engines are completely new small - block designs based on architecture similar to that of the Corvette ' s LS1 engine.

The base powerplant remains the 4. 3 - liter / 200 - horsepower V - 6. But a new chapter starts with the next engine up the ladder, a 4. 8 - liter / 255 - horsepower OHV V - 8. This engine, the new 5. 3 - liter, and 6. 0 - liter V - 8 engines are all fresh designs with cast - iron, deep - skirt blocks and six - bolt caps for all five crank bearings. The aluminum heads are new designs with extra - long bolts and redesigned head gaskets for better cylinder sealing and new port designs for deeper breathing. Powertrain Engineering also specified a structural aluminum oil pan and a die - cast aluminum valley cover for greater rigidity and lower vibration and noise. And finally, all the new engines feature electronic coolant - loss protection that allows them to be safely driven, in a limp - home operating mode, without any cooling fluids.

The 4. 8 V - 8 will take the place of last year ' s 5. 0 - liter / 230 - horsepower powerplant. Interestingly, where that previous 5. 0 - liter engine made its 285 pound - feet at 2800 rpm, the new 4. 8 engine hits its 285 torque peak at 4000 rpm. According to Tom Stephens, group director of engineering for the GM Truck Group, this high - rev torque curve " better suits pulling long, steep grades. " ( We ' re skeptical. ) Replacing the light - duty 5. 7 - liter / 255 - horse engine is a 5. 3 - liter making 265 horsepower at 5000 rpm. And although it doesn ' t quite make the 330 pound - feet of torque generated by the old 5. 7, it ' s only shy by 10 pound - feet at the same low 2800 rpm. For real workhorse applications, the 6. 0 - liter V - 8 with 300 horsepower and 350 pound - feet of torque will get the job done in place of the heavy - duty 5. 7 V - 8. And if the 6. 0 is somehow shy of grunt for some super - duty task, customers can still order the big - gun 6. 5 - liter turbocharged diesel. For ' 99, its power jumps by 25 horsepower to 215, and its wall of torque surges to 440 pound - feet at 1800 rpm from last year ' s 385. The torquey, but gas - swilling 7. 4 - liter big - block has not, so far, been given the green light for use in the new trucks.

All the GM light - and heavy - duty transmissions have been beefed up with special emphasis on the automatics paired with these engines. For example, fluid volumes have been increased and sump drain plugs and fluid - temperature gauges have been added. The final transmission tweak is a new button - selectable, electronically controlled shift schedule tailored for trailering and heavy loads. Additionally, now there will be manual and " active " transfer cases for 4x4 - equipped trucks. The quieter, fuel - efficient active case sends power to the front wheels only when the rear axle slips.

Very significant is the all - new three - piece frame design that GM says is 23 percent stiffer and 64 percent stronger than before. The goal here is to help provide better ride and handling while keeping the inherent truck toughness buyers demand. The frame ' s front section is built using the same high - tech hydroforming technology pioneered on the new Corvette ' s frame. The front tubular - steel section carries the powertrain and front suspension, and manages the crash forces in the event of an accident.

The center roll - formed frame section carries the cab, handles off - road twisting forces, and acts as a bridge and " fifth spring " between the front and rear axle. The rear section carries the bed payload, suspension loads, and trailer - tow forces. Connecting the parallel frame rails are now tubular steel crossmembers that actually poke all the way through each side and are welded in place. Neither Ford nor Dodge offer anything this complex.

One of the most important upgrades in the new trucks is to their braking systems. Standard equipment will be a four - wheel disc system with a more sophisticated anti - lock controller that GM promises will provide class - leading fade resistance and stopping distances, especially when laden. Most of the competition offers front - wheel discs and four - wheel anti - lock only as an option.

Despite all the changes in the chassis design, the suspension system remains relatively conventional. On two - wheel - drive versions the front suspension is made up of basic coil springs and A - arms. On four - wheel drives, the front springing element is a torsion bar. Both 4x2 and 4x4 versions will use a live rear axle fitted with wholly - conventional leaf springs.

Of course, the real evaluation can ' t take place until we strap our test gear into one of these new pickups and see for ourselves if General Motors has built a winner or a wimp.