2015 GMC Sierra 2500/3500 HD: First Drive

GMC introduced its significantly refreshed 2015 Sierra Heavy Duty pickup trucks at the 2013 State Fair of Texas last September and created quite a buzz in the truck world. Remember, this was the same fair where Ford debuted its 2015 Super Duty F-450. Just a few months later Ram showed off the changes to its 2500 and 3500 models, so creating buzz in this arena is not an easy task. Clearly, the Heavy Duty Truck War is heating up and will be quite a battle in the months and years to come.

We recently had our first chance to get behind the wheel of the new 2015 GMC Sierra 2500 and 3500 pickups, and we can say they are a solid jump ahead of what they are replacing, making up significant distance to and beyond the competition. Some may complain GMC didn't go far enough, but you have to consider it was just three short years ago that GM engineers completely redesigned the heavy-duty frames and suspensions and offered a new pair of powertrains. Now it's time to revamp the cab configurations, gut the interior and make a few clever bed modifications. The result? The GM engineers have created new trucks that are greater than the sum of these specific improvements and built two of the strongest players in the segment. Yes, all this and it's just a "refresh," but there is some meat here too.

Although the engines carry over, GM engineers have done extensive work with throttle and braking response calibration, working to better integrate the transitions coming to a stop, as well as how smoothly braking controls heavier bed and trailer weights around corners, even when nearing maximum gross combined weight ratings. Both StabiliTrak and trailer-sway control are standard on most models, and a hill-hold feature was also useful on our steep hillclimb stop.

In regard to the engines, power ratings for both the 6.0-liter V-8 gas engine (360 horsepower/380 pounds-feet of torque) and the Duramax 6.6-liter V-8 turbo-diesel (397 hp/765 pounds-feet of torque) remain the same but are better calibrated to get as much torque through the two-wheel and four-wheel drivetrains as possible. GM engineers worked hard to make sure they got as much power as possible to the rear wheels through the transmission at both a standing start and at speed.

GM had a Ram 2500 HD with the high-output Cummins and Ford Super Duty F-250 with the Power Stroke on hand for us to drive up and down a 6 percent grade for back-to-back testing. The drive proved informative, especially when comparing exhaust brake systems and strategies for controlling trailer weight. For our test drive, each truck was equipped with a 10,000-pound trailer with the cruise control set at 55 mph at the top of the hill (tow/haul engaged, exhaust brake switch — where equipped — to "on" or "full"). Note that the current Super Duty has no manually selectable exhaust brake; it is connected to tow/haul activation.

What we found was that the GM setup held the truck and trailer comfortably at or near a constant speed with an easy-to-understand setting. The Ram HD's Smart Brake, although capable of accomplishing a similar result, offers several more options and settings. We've been a fan of the Smart Brake from its introduction, but we think the GM setup is much simpler.

On the uphill climb, during side-by-side roll-off starts at 30 mph to 50 and 60 mph, the Duramax was the runaway champion that we've found it to be our 2011 Heavy-Duty Hurt Locker and Rumble in the Rockies tests. We should note that the single biggest detail that separated these three heavy-duty haulers on our informal runs up and down Arizona's Rye Grade hillclimb was how quiet the interior of the GM trucks were. How well the engines performed did not surprise us.

The Duramax has always been a fairly quiet engine, especially when compared to the Power Stroke and Cummins, but with the new GMC cab structures (all of which have more high-strength steel and sound-deadening material in the firewall than ever before) and interior layout, the sound levels were the big surprise of the tow test. We know many passionate towing enthusiasts like the sound their diesels make, but we have to say the insulation helped turn our long drives through the mountains of Arizona and back down into Phoenix traffic a much more relaxing and comfortable experience. That's a benefit many buyers may be unaware of unless they have a lot of big-truck towing experience.

Also related to interiors, we must mention GM's highest-level trim package — the Denali. We've always liked the Denali package, but we like that fact it now uses real aluminum and wood trim accents in the HD lineup, as well as a unique, digital, programmable gauge cluster. Although the 2015 Denali (offered across the double and crew-cab 2500 and 3500 lineup) is a good trim package, we think it still falls short of Ram's Laramie Longhorn and maybe even Ford's Super Duty Platinum offerings. We'd still like to see more exclusive technology and possibly a Denali Plus edition.

One piece we especially like about the GMC when compared to its Chevrolet brother, is that many of the optional features on the Silverado HD are standard equipment on a similarly packaged Sierra HD. As with the light-duty trucks, you can expect GMC models to carry a slightly higher price for a similar level, but they will include more equipment. The GMCs will offer four separate trim packages: the base Sierra, SLE, SLT and the premium Denali.

We got to drive both the SLT and Denali packages and were impressed with the upgraded material uses and stylish stitching over the dash seams and in the seats. The revised interior, available in both the Silverado HD and Sierra HD, offers several power plug ports, five USB plugs and even a three-prong inverter. These are huge improvements in both the GM light-duty and heavy-duty lineups that other manufacturers should pay close attention to.

Pricing for the 2015 Sierra 2500 and 3500 can be found on the GMC website. Some of the first models were sold just this week. We'll be inviting both the GM heavy-duty pickups to a tow-testing head-to-head challenge later this summer, where we hope to find out exactly how well these newly refreshed models compare to the all-new 2015 Ford Super Duty headed our way, as well as the current King of Beasts champion, the Ram 3500 HD. More testing of the GM HDs and the other competitive pickups is on our calendar.

For the most up-to-date specifications for the 2015 GMC Sierra 2500, click here.

For the most up-to-date specifications for the 2015 GMC Sierra 3500, click here.

Comments (29) in First Drive, Full-Size, GMC, GMC Sierra 2500, GMC Sierra 3500, Heavy-Duty, New Trucks, Towing and Hauling