2006 Chevrolet Silverado Review

Specifications

Duramax/Allison Partnership Prove Might is Right

The hiss generated by the high-pressure, variable geometry turbocharger force-feeding GMs massive 6.6-liter (403 cu-in) Duramax diesel V8 gave my prodigious Silverado 2500HD 4X4 tester the acoustics to match its stunning torque rating of 650 pound-feet. Accompanying the mountain of torque in the new-for-2006, larger Duramax is 360 horsepower. Thats the kind of brawn needed to pull 5th wheel homes and horse trailers through mountain passes without holding-up traffic like a cork in a bottle. With so much pulling power at one end and dead weight at the other, an automatic transmission was often the weak link in an otherwise very strong chain. For 2006, GM has hardened the susceptible weak link by bolting a 6-speed Allison-manufactured autobox to the rear of its “bruiser,” Vortec 8100 (gas) and Duramax 6600 (diesel) powerplants.

The Duramax/Allison partnership is definitely the Silverado highlight this year. The big Duramax was engineered to pump-out segment-leading torque while delivering 15 to 20 percent better fuel economy than GMs current 6.5-liter turbo diesel, although official figures have yet to be released. During my heavy-footed time behind the wheel, the vehicles driver information screen displayed an average fuel economy rating of 13.3 miles per gallon. Despite these pocketbook-crushing results, GM claims to be setting new industry standards for fuel efficiency, diesel power and performance in the heavy-duty pickup class with the Duramax 6600.

According to GM, not only is their new “oiler” more efficient than previous GM diesels, its quieter too. Noise, vibration and harshness (NVH) figures, based on GM literature, are comparable to similar-sized gasoline engines. After spending a week behind the wheel of my tester that included both city-traffic plodding and open highway cruising, Im not prepared to validate GMs NVH claim. From ignition to shutdown there is no doubt that the Duramax 6600 is drinking diesel; nonetheless I was impressed with the civility of the big workhorse. This engine is a pleasure to administer.

Thanks to revised glow plugs, the new Duramax starts instantly. Once underway it pleases with delightful-for-a-diesel operational refinement while delivering abundant power in a smooth, progressive manner - and boy can it kick. I was quite surprised by the Silverados take-off punch and its no-holds-barred passing ability. After the Allison gearbox takes a moment or two to insert the most suitable cog, the big truck storms ahead with unrelenting ferocity. With a range of six gears and 650 foot-pounds of torque at only 1,600 rpm, there were simply no flat spots in the acceleration continuum to impede the hastening of my testers 5,883 lb curb weight. With shift-points coming at 3,200 rpm when the pedal is on the metal, the more gears available, the better.

With its half dozen cogs, the Allison tranny is worthy of a review dedicated solely to its sophisticated technology. Rather than befuddle readers - and myself - with such minutiae, I will hit the aspects important to most purchasers and leave the techno-babble to those with plenty of time to search-out the finer details. As with modern automatic gearboxes, placing the shifter in “D” relieves the driver of any need to participate in shifting gears. The Allisons Adaptive Shift Control feature will select the appropriate gear by analyzing engine torque and vehicle speed. In doing so, it will minimize unnecessary up-shifts and down-shifts. A Tow/Haul mode can be instantly activated with a button situated at the end of the gearshift stalk. The Tow/Haul mode alters shift patterns in order to maximize the engines efficiency in both pulling and braking. When the Tow/Haul function is activated, Grade Braking is also engaged. In an effort to maintain the vehicles speed when descending a grade, the electronic program inserts a lower gear to improve engine baking, even when the truck is operating under Cruise Control.

Perhaps the most useful to drivers wanting more human input into shift patterns is Allisons Range Selection Mode, which enables manual, electronic shifting between the six gears. Positioning the shift lever in “M” activates a small rocker switch near the end of the gearshift stalk. The button corresponds with a small LED readout in the instrument panel depicting gears 1 through 6. Moving throughout the gear range is as easy as rocking the button up or down. The Range Selection Mode makes manual shifting as easy as it gets, which pretty much describes driving the bulky Silverado on pavement or off, thanks to its shift-on-the-fly four-wheel-drive (4WD) capability. When things get severely ugly, engaging a low-range set of gears while locked in 4WD is simply another button-push away. When the mucky stuff gives way to asphalt, the Silverado quickly softens its rugged demeanor.

At posted highway speeds and slightly above, my tester generated very little road and wind noise, especially for a hulking pickup truck. Regardless of speed the big rig remained stable and steady while encountering side winds and undulating pavement, however, over sharp bumps the firmness of its real leaf springs induced a choppy, somewhat bouncy ride. When compared to the harsh ride of other heavy-duty 3/4 ton 4X4 pickups I have contended with, the Silverado has no apologies to make. Adding a little weight to the empty box would undoubtedly excise some of the ride discomfort, but even without the weight advantage, the Silverado 2500HD is a tremendously comfortable highway cruiser. On smooth pavement it loafs along in 6th gear turning well under 2,000 rpm to maintain typical highway speeds. Much of the Silverados comfort can be attributed to its expansive cabin and first-rate seating.

The heated, leather-upholstered captains chairs in the fore cabin of my tester were wonderfully supportive and widely adjustable, easily accommodating most driving positions, although the inclusion of a left foot dead pedal would increase leg comfort and enhance the drivers connection to the vehicle. A large center console and storage bin separates the comfy front perches. Less-positive comments pertain to the out-dated instrument panel facing the driver; yes it clusters together a full complement of gauges but not within a modern setting such as in GMs new line of Yukon and Suburban SUVs. The European-influenced dashboard in those new offerings do away with the plastic framing and sharp angles that define the Silverados tall, upright dashboard. Nonetheless, theres nothing missing in the Silverados rendition other than class and visual appeal.

Comfort aboard the Crew Cab Silverado isnt just a front seat virtue. The spacious rear seating area is also remarkably comfortable as crews quarters go, replete with air conditioning outlets and private audio. Of course all this interior real estate comes at a price beyond monetary; the crew-cab-equipped Silverado is a lengthy beast. My tester, which held the standard cargo box of 78.7 inches in length, was a shade too long to fit into my garage. If I had removed the work bench at one end, the Silverado would have fit with approximately 12 inches of room to spare - and I have a large garage. At the end of my street is a cul-de-sac turn-around. Before the Silverado, I had never tested a vehicle that was too large to turn around in this circular space without backing up. The huge 49.6 foot turning radius of the crew-cab-equipped Silverado conspired with its overall length of 237.3 inches to defeat my “no-need-to-reverse” record. Amazingly, the Silverado can grow even longer when the 97.6 inches long, full-length cargo box is attached. This would bring the Silverados maximum overall length to a solar eclipsing 256.2 inches - yikes.

Realistically though, these behemoths are necessary assets for those involved in farming and industry; or those pulling retirement homes to desert climates. Chevy has done a very good job of providing the means to easily and comfortably accomplish a variety of major automotive tasks with the Duramax-powered Silverado 2500HD 4X4. Oddly enough, I enjoyed driving my tester in and about town. Its girth brings a relaxation to driving that simply isnt there when I drive smaller, sportier vehicles. I think the Silverado-induced sense of solace arises from knowing there is no ability to jump from lane to lane in an attempt to get ahead of slower traffic. In the enormous Silverado, time just slows down while its satellite radio plays whatever genre of music happens to be mood matching at the time.

Along with satellite radio, Chevy has ensured that buyers of Silverados are free to load-up the truck of their needs with a wide array of comfort and convenience items, provided the yearned-for items dont include a multitude of airbags. Only driver and front passenger airbags are available, which is somewhat disappointing. Fortunately powerful, antilock 4-wheel disc brakes are standard equipment on all Silverados, as is traction control on 2WD models. Theres plenty of competition at present between the big-3 domestic automakers about whose truck is biggest and most potent. That is really up to the customer to decide after careful analysis of the specs, capacities and performance ratings. Suffice to say though if its the Duramax/Allison-equipped version of the Silverado 2500 HD 4X4 Crew Cab rolling into your driveway, you have just secured king-of-the-hill bragging rights… for this year at least.