Who needs 660 pound-feet of torque? Someone who needs to drag 13,000 pounds around, that's who. And the only 3/4-ton truck that can tackle that job is Chevy's Silverado 2500 HD armed with the optional 6.6-liter Duramax diesel V-8, which TheCarConnection.com drove — and admired — during a recent test.
Chevy's he-truck edges out the Ford F-250's 6.4-liter Power Stroke diesel, which has a maximum tow rating of 12,500 pounds and 10 fewer pound-feet of torque. And it out bench-presses the Dodge Ram 2500 even when that truck is ordered with the newly available 6.7-liter Cummins turbodiesel. (This new engine replaces the Ram's old 5.9-liter diesel and produces and impressive, but still second place, 650 lb-ft of torque.)
Both the Ford and Dodge diesels offer less peak horsepower, too. The Chevy's Duramax weighs in with a class-leading 365 hp vs. 350 hp each for the F-250's Power Stroke and the Ram's Cummins.
Another unique draw of GM's 3/4-ton truck is the heavy-duty six-speed Allison 1000 automatic transmission — a mandatory upgrade when you choose the Duramax diesel engine. This is an incredibly beefy unit designed to stand up to the frame-twisting output of the Duramax V-8. It also has different gear ratios designed to take best advantage of the diesel's massive low-end grunt. Since all 660 lb-ft is available at just 1600 rpm, the Allison's first gear ratio is 3.10 (vs. 4.03 for the gas engine's six-speed automatic) while fourth gear's 1.00 (vs. 1.15). And the final drive ratio with the diesel is 3.73 — vs. up to 4.10 with the 2500's standard gas-burning 6.0-liter V-8 engine.
The taller gearing keeps the diesel V-8 operating closer to its torque peak off the line and under hard acceleration or while pulling a heavy load, while also keeping highway revs (and engine racket) down. In sixth at 70-something mph, the big truck lumbers along quietly with the engine barely turning a fast idle around 1700 rpm.
2007 Chevrolet Silverado 2500HD
Mileage figures for the Duramax diesel were not available at the time of this writing; however, the diesel's city/highway numbers should be comparable to, if not better than, the 2500's standard 6.0-liter gas V-8. And that engine only musters 373 lb-ft of torque, nearly 300 lb-ft less than the Duramax belts out.
The Allison 1000 transmission also has both Tow/Haul mode with grade braking and a driver-selectable manual mode — with a thumb-activated switch on the column shifter. There's an integrated Trailer Brake Control on the lower left dash, too (when ordered with the optional towing package). A "low traction mode" enables second gear starts to limit wheel slip on slick surfaces.
Of course, muscles without finesse can be as unwelcome as an angry gorilla in your living room. But despite its class-leading towing and hauling capabilities, the Silverado 2500 is an easy driver. The Allison transmission shifts positively, but without lurching you forward and then back again, as HD gearboxes sometimes do. And the turbocharged, direct-engine diesel engine is a very pleasant companion. You can hear yourself over the idle when you roll down the window at a drive-thru — and on the highway, in top gear, the engine is almost completely muted.
The leaf-sprung/torsion bar/short-and-long-arm suspension, meanwhile, may be tough as a tank — but the ride quality is comparable to any light-duty half-ton truck or full-size SUV.
GM did a really super job on the Silverado 2500 — and not just drivetrain-wise. The interior (layout and materials) is orders of magnitude better than any previous GM truck — nicer, in fact, than the interiors of some of GM's luxury cars used to be. High-trim LTZ versions are downright posh, with multi-stage seat heaters, handsome leather seats and rain-sensing wipers (with heated washer fluid), power sliding rear window, power adjustable pedals, navigation systems, and a rear-seat DVD player among the available amenities. It's no chore to pull a horse trailer (or boat) halfway across the state in one of these things.
It's true the all-new '08 F-truck is equally nice in those respects, especially on the inside, where it really shines. But again, it's not quite as capable. And the Ram 2500's a brute in looks and feel, even though it's not quite as strong as the more docile-seeming, better-mannered Chevy.
The Duramax diesel's not a cheap date, however. It adds $7195 to the tab, plus another $1200 for the mandatory Allison 1000 six-speed automatic. On the other hand, a less-capable truck that might not be able to handle what you need it to could end up being even more costly in other ways, from premature failures to simply not being up to snuff.
A footnote: Buyers looking at this truck (and this engine) should be aware that the Duramax V-8 must be fueled with Ultra Low Sulfur Fuel (ULSF) with no more than 15 parts per million (ppm) sulfur content. The Duramax has a self-cleaning particulate trap that captures 90 percent of the soot that would otherwise belch out of that massive five-inch tailpipe. Use of older Low Sulfur Fuel (LSF), which has 500 ppm sulfur content, is a major no-no that could damage the vehicle's emissions system and leave you with a big repair bill. Be sure ULSF fuel is readily available where you live — and plan to drive.
Other than that, this truck's ready to roll — and ready to handle anything you can throw at. Or plan to pull behind it.
2007 Chevy Silverado 2500 HD Crew
Cab LTZ Duramax
Base price: $36,485; price as tested: $49,859
Engine: 6.6-liter turbodiesel V-8, 365 hp/660 lb-ft
Transmission: Six-speed automatic, front- or four-wheel drive
Length x width x
height: 239.5 x
79.9 x 77.1 in
Wheelbase: 153 in
Curb weight: 5,742 lb
Fuel economy (EPA cty/hwy): TBA
Safety equipment: Driver and front-seat passenger airbags; anti-lock brakes
control; power windows and locks; multi-level heated front seats; auxiliary
engine oil and transmission fluid coolers; leather and wood trim; premium audio
with seven speakers and six-disc CD changer and MP3 capability
Warranty: Three years/36,000 miles