BIG BAD JIMMY
2012 GMC Sierra HD 4X4 Denali

He stands seven-eight and weighs 6307. Kinda broad at the shoulder and narrow at the hip. And everybody knows you don’t give no lip to Big Jimmy. That is, Big GMC Sierra HD 4X4 Denali Jimmy with the 6.6 liter Duramax engine and Allison transmission under the hood. Light duty trucks, step aside. Big bad Jimmy is here, and Harvey Schwartz reports. By Harvey Schwartz Pickup trucks continue to be the best-selling vehicles in the industry because of their versatility and functionality. Most are light duty models that can take care of most needs, but when you need maximum torque, towing power, size and interior room and comfort, nothing beats the new GMC Sierra Denali with the 6.6 liter Duramax turbo-charged diesel engine matted to the Allison 1000 six-speed automatic transmission. The numbers are big and heavy duty—just what you need when towing extra heavy loads or workmen with equipment to a job site. The new truck has a best-in-class maximum towing capability of 23,000 pounds, best-in-class conventional-hitch trailering capacity of 18,000 pounds, best-in-class maximum payload of 7,215 pounds, best-in-class GCWR rating of 30,500 pounds, fully boxed high-strength-steel frames, standard 36-gallon fuel tank enabling 680 miles of travel between fill-ups, Smart exhaust brake feature provides greater control on grades and reduced brake pad wear, an array of control features including trailer sway control, integrated trailer brake control, hill start assist, automatic grade braking, intelligent brake assist and large 13 plus-inch brakes.

Optional hard-drive navigation radio with AM-FM-Sirius XM stereo with CD/DVD player, MP3 compatibility and USB port, cruise-control and spare tire lock are now standard with Work Truck models. Rain-sensing wipers, outside vertical camper mirrors now standard, heated and cooled front seats, leather-wrapped heated steering wheel and rear vision camera are now standard on Sierra Denali HD models like we tested. A high-idle switch is now available on 2500 Denali HD, plus 20X8-inch wheels and matching tires are available on the Denali 2500 model. The Denali-specific bullet-hole chrome grille makes the trunk instantly recognizable. Additional chrome trim and body-color bumpers further distinguish it. Sierra Denali also offers a unique combination of interior style and luxury including standard nuance perforated leather appointed front bucket seats with heated and cooled 12-way power adjustments. A Denali exclusive leather-wrapped and heated steering wheel which features wood-grain accents and a host of auxiliary controls is standard. Technology features include optional WiFi, USB connectivity, Bluetooth, OnStar 9.0 and navigation that help make work on the road easier. Denali models feature a unique center console, enhanced interior bright work and detailed, highly finished embossed sill plates. The center console has woodgrain trim and a lid that conceals the dual cup-holders creating a more finished and refined appearance.

The 2012 Sierra Denali model makes work and play so much easier with these features-dual-zone automatic climate control, driver information center, rear-seat entertainment system, auto-dimming rearview mirror, heated outside mirrors, power-adjustable pedals, remote vehicle starter system, power sunroof and power operated rear sliding window. Helping the GMC Sierra Denali HD 2500 4XD achieve best-in-class 397 horsepower at just 3,000 rpm and 765 pound-feet of torque at just 1,600 rpm is the Duramax 6.6 liter turbo diesel and Allison 1000 six-speed automatic transmission. The engine features a high-pressure (30,000 psi/2,000 bar) Piezo-actuated fuel system for greater fuel efficiency, improved performance and reduced emissions. An exhaust brake system enables controlled vehicle slowdown on downhill grades without actuating the brakes. The Allison 1000 features a driver shift control with tap up/tap down shifting and a patented elevated idle mode cab warm-up feature. Also, the tow/haul mode reduces shift cycling for better control and improved cooling when towing or hauling heavy loads. The increases in payload and towing capacity are due to a variety of enhancements, including beefier rear springs, and U-bolts, revised rear axle tubes and shock tuning, revised pickup box cross sills and other structural enhancements too numerous to mention. All Sierra HD models feature fully boxed frame assemblies that were redesigned last year with reinforced cross sections and use more high-strength steel for greater durability, higher towing capacity and improved ride and handling. The front sections are hydroformed. Additional chassis and suspension features include: front axle weight rating up to 6,000 pounds front gross axle weight rating enabling a snow plow to be used on all 4X4 models, a short arm/torsion bar front suspension that features forged steel upper control arms and precision-machined cast iron lower control arms, five different torsion bar rates that support five different front gross axle weight ratings to help stabilize the range of trim heights of various models under load while enhancing appearance, handling durability, tire wear and alignment.

The trim height is adjusted on each bar via a single bolt, easily allowing the height to be changed to account for the weight of a snow plow or other accessories. An upper shock mount attachment design that’s positively connected to the frame with two fasteners eliminates squeaks and clunks while supporting higher load capacity and increased durability. The asymmetrical leaf-spring design minimizes axle hop and enhances traction control efficiency. The two-stage leaf-spring design on the 2500HD models features three-inch wide leaf springs. Four-wheel power-assisted disc brakes with hydro-boost is standard on all models, including four-wheel, four channel ABS. Sierra HD safety features and crash avoidance features include StabiliTrak electronic stability control with all single-rear-wheel models, large 4-wheel disc brakes, seat pelvic/thorax and head curtain airbags, rear vision camera, trailer sway control system and hill start assist on single rear wheel models. Virtually every available engineered and high-tech feature makes the new GMC Sierra HD Denali pickup right for every job or fun adventure that you can think of. It is my choice for HD trucking. © Words and pictures by Harvey Schwartz SUMMARY JUDGMENT At the bottom of this article lies the specs for a big, big truck. For more information about GMC products, go to www.gmc.com

SPECIFICATIONS Name of vehicle: 2012 GMC Sierra 2500 4X4 Crew Cab Denali Price: $62,440.00 loaded as tested Engine: 6.6 liter cast iron block/aluminum head, OHV direct injection, turbo charged/intercooled V8. Horsepower: 397 at 3,000 rpm Torque: 765 pound-feet at 1600 rpm Transmission: Allison 1000 six-speed automatic/OD with ‘tap shift’ Suspension Front: Independent long/short arm torsion bar/gas-charged shocks, stabilizer bar Rear: Semi-elliptic two-stage multi-leaf springs/gas-charged shocks. Brakes: Power-assisted Hydro-Boost brake system/ABS/Traction Control/Stability Control Front: 13.8 inch vented/dual-piston calipers Rear: 14.1 inch solid discs/single-piston calipers Wheels/tires: Denali standard 20X8in. polished aluminum wheels/LT265/60R20in. all terrain tires Dimensions Overall length: 240 inches Overall width: 80 inches Overall height: 78 inches Curb weight: 6307 pounds