Who needs 660 lbs.-ft. of torque? Someone who needs to drag 13,000 lbs. 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.

Chevy's He-truck edges out the Ford F-250's 6.4 liter Powerstroke diesel - which has a max tow rating of 12,500-lbs. and 10 fewer lbs.-ft. of torque. And it out bench-presses the Dodge Ram 2500 - even when ordered with the newly available 6.7 liter Cummins turbo diesel. (This engine replaces the Ram's old 5.9 liter diesel and produces and impressive - but still second place- 650 lbs.-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 PowerStroke and the Ram's Cummins turbodiesel engine.

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 lbs.-ft. is available at just 1,600 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 1,700 RPMs. In addition to less engine noise in top gear, the lower operating speeds should also reduce wear and tear - and helps optimize fuel efficiency. The less you have to work the engine, the less fuel you'll burn. (Mileage figs. 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 lbs.-ft. of torque - nearly 300 lbs.-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.

Another neat (and unique) feature of this ultra-duty automatic is an "elevated idle mode" which kicks in when the vehicle is cold-started to shorten warm-up times by slightly increasing the load on the engine - even when the transmission is still in "park" or "neutral." (If the vehicle is in motion, part-throttle upshift points are temporarily raised, too.) The slight loading effect at idle is itself not noticeable to the driver. The truck just reaches normal operating temperature faster than it otherwise would.

Ford's just-redone/2008 F250 doesn't offer a six-speed automatic; a six-speed manual is this truck's standard gearbox - with a five-speed automatic available optionally. The updated/2007 Dodge Ram 2500, for its part, does offer a new six-speed automatic with the Cummins turbodiesel - but like the F-truck, the Ram can't out-tow or out-haul the king-of-the-hill Chevy.

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, you can hardly anything at all. 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, GPS navigation and 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 $7,195 to the tab - plus another $1,200 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.

If you need the most, then you need the Max. It's pretty self-explanatory.

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 5-inch tailpipe. Nox emissions are cut in half, too - exceeding current federal standards. But in order to make that cut, it is imperative that ULSF fuel be used. Without exception.

Use of 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.

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