HD Chevy 2500 LTZ, Duramax and 6-speed Allison Auto, Hard to Beat

2011 crew cab, it has it all for a HD truck.

All the toys, if you're not use to the ride of a HD, you might think it harsh. Yes compared to a Cadillac but for HD pickups, it's a nice ride. Center console is more accessible as it slants out for easy reach of controls. Buttons for volume under the steering wheel, remote start, starts instantly, so quiet, you think it's a car. Exhaust brake is great and works seamlessly with the Allison auto, but the light on the switch is hard to see if it's on.

Now for 2011, GM went massive truck improvement, as in frame, suspension, payload and towing ability puts Chevy and GMC HD trucks at the top of their segment. It's improvements we all want and of course the power and fuel mileage have also improved. The new suspension keeps the power under control and tires planted on the pavement. The new exhaust brake adds stopping power to grade shifting from the Allison tranny and larger brake rotors this year.

New steering box, ratio's and linkage add up to tighter steering changes and the new hydraulic body mounts on the C-pillar, improved the crew cab ride. It's a truck that takes the work out of all day towing on what's left of our Interstate highways and finally a 36 gallon fuel tank to find the cheaper fuel at the next town.

Duramax (LML 397 hp, 765 torque) diesel. The Allison grade shifting and the new exhaust brake kept my foot off the brake. The exhaust brake closes the vanes on the turbine side of the turbo to create back pressure. It's fully integrated with the Allison 1000 6-speed automatic transmission. The exhaust brake has an on/off switch with four operational modes: tow/haul mode engaged, tow/haul mode disengaged, cruise control on and cruise control off. So you can toggle down gears by switching from auto to manual with the cruise on, it's just too easy.

The new GM steering was smooth and easy, I could see the trailer brake controller gain in the instrument cluster close to the gauges I watch. Using tow haul mode with a trailer, down shifts are early to hold for more braking, holding range longer so less gear hunting which is fully integrated with the exhaust brake.

And they get better when loaded, 14" rotors, almost the same size front and back with more than an one inch increase, and proportional brakes that can change pressure front to back where the most brakes are needed with a load. I remember on the farm driving mostly on dirt roads. That gravel ate my trailer brake magnets, so I knew my trailer brakes wouldn't always work, duals helped but GM can balance brake pressure to help with the tongue weight of a trailer pushing on the wrong end for max braking. The hydroboost brake booster calibration takes less pedal effort.

2011 GM SRW trucks have trailer sway control with integrated trailer brake control, to brake the sway out of a conventional trailer if the problem arises. A big deal for trailer safety. With hill start assist, the truck and trailer brakes hold a couple seconds while you go from brake pedal to gas pedal. The revised Allison auto has automatic grade braking, intelligent brake assist and exhaust brake on the Duramax diesel. Towing trailers is getting safer and easier.

New asymmetrical design is from unequal front and rear spring half lengths, which minimize axle hop and enhance traction control efficiency better than anything I've had on pavement. StabiliTrak electronic stability control system on all single-rear-wheel models greatly improves an empty trucks handling on slick roads. 2500HD models feature a two-stage leaf-spring design, while 3500HD models have a three-stage design. All models feature 3-inch-wide leaf springs that are 20-percent wider than previous models.

The larger leaf-spring design supports increased rear gross axle weight ratings across the board. On the 2500HD models, the rating is 6,200 pounds, up from 6,084. On 3500HD models, the rating increases to 7,050 pounds on single-rear-wheel models and 9,375 pounds on dual-rear-wheel models, the latter representing a nearly 14-percent increase over the previous 8,200-pound rating.

2011 GM 3500 duallys can tow up to 21,700 lb gooseneck/5th wheel trailers with a 6635 lb payload. GCWR is 29,200 lbs, 17,000 lb conventional trailer without weight distributing. That's impressive, SRW (single rear wheel) trucks are rated at 13,000 lbs conventional trailer without WDH (weight distributing hitch) and DRW (dual rear wheel) trucks are rated at 17,000 lb without WDH.

The independent front suspension has forged steel upper control arms, cast iron lower arms with bigger shock towers and a pair of urethane jounce bumpers on each side, instead of one. Torsion bars and torsion bar attachment frame is larger and adjustable. 5 different torsion arms rating instead of one. 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

The new emissions diesel uses urea (DEF) which basically costs what it saves in improved MPG (2% diesel exhaust fluid or urea). The tank is outside the frame under the passenger side of the cab, picture left. It holds 5.3 gallons with a range close to an oil change 5, 000 to 8,000 miles. The fill cab is under the hood (picture left,) easier for filling with gallon jugs.

Combustion and after-treatment have been optimized to provide about 700 miles between diesel particulate filter regenerations, a 75-percent improvement over the previous system and significant contributor to improved fuel efficiency, as the regeneration process requires extra fuel.

Improvements to the new Allison 1000 6-speed auto include torque converter with a new two sided lockup clutch, twice as much as before to handle the extra power from the LML Duramax. A new stator for torque multiplication new valve body, modified clutches, stiffened case for drive train power and larger output shaft on 4x4's. Fifty-seven new parts, made for the extra diesel power and new integrated exhaust brake.

Chevrolet 2011 Silverado 2500 4WD LTZ Crew Cab 10,000 lb GVW as reviewed.

Off Road Suspension Package:     $275

Off Road Skid Plates

LTZ Plus Package:                       $725

Locking Tailgate, EZ Lift Tailgate, Universal Home Remote, Rear Wheel house liner, Adjustable pedals and rear park assist

Duramax 6.6L V8 Turbo Diesel:     $7195

Allison -Speed Automatic Trans:    $1200

20 in Forged  Alum Wheels           $850

Rear Vision Camera System         $420

Head Curtain Front air bags          $395

Mirrors, Camper Style, Heated      $55

As Equipped                               $57,824 

Changes for 2012 HD

For enhanced fifth-wheel towing, engineers strengthened the pickup box sills and other box structures, rear springs, u-bolts and box mounts, and upgraded the shock tuning. As a result, GM 3500HD now has a best-in-class tow rating of 23,000 pounds, up from 21,700 pounds in 2011.

GM also will lead the class in dually payload, with a 7,215-lb. payload for the 3500HD regular cab gasoline dually. Updates to the trailer hitch receiver increase conventional towing to 18,000 pounds, up from 17,000 pounds. Both changes will be on models arriving in dealerships in the fourth quarter.

Other updates for 2012 Sierra HD trucks include a new navigation radio with enhanced display and a hard drive, eliminating the need for discs with map data.

Sierra continues to offer OnStar, a segment exclusive, SiriusXM satellite radio, Bluetooth for phone and USB connectivity.