With its half dozen cogs, the Allison tranny is worthy of a
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| The 6-spd Allison transmission is probably the most technically innovative part of this truck. (Photo: Rob Rothwell, Canadian Auto Press) |
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 Allison's 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 engine's efficiency in both pulling and braking. When the Tow/Haul function is activated, Grade Braking is also engaged. In an effort to maintain the vehicle's 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
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| Simple push-button transfer case is easy to use. (Photo: Rob Rothwell, Canadian Auto Press) |
the most useful to drivers wanting more human input into shift patterns is Allison's 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
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| Bouncy ride when the bed's empty, but when loaded, the ride ought to quiet down. (Photo: Rob Rothwell, Canadian Auto Press) |
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 Silverado's comfort can be attributed to its expansive cabin and first-rate seating.
The
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| Leather seats: a comfort feature, but also a convenience feature. It's much easier to wipe down than cloth. (Photo: Rob Rothwell, Canadian Auto Press) |
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 driver's connection to the vehicle. A large centre 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 GM's 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 Silverado's tall, upright dashboard. Nonetheless, there's nothing missing in the Silverado's rendition other than class and visual appeal.
