2015 GMC Sierra 2500/3500 HD: First Drive

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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.


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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.

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@Mark Williams will there be another shoot out or we waiting for 2015 Fords maybe 2015 Rams also?

If it's anything like them providing trucks for Roman to drive from the FLT, they made sure the GM had some advantage. After all, it is GM staged.

GM tried to pull a fast one on FLT and got Roman to drive a 6.2 GM with 3.73s, the Ford Ecoboost had the 3.73, and of course, GM had to water down the Ram so their GM truck looked better, so the brought in a 3.55 geared 6 speed, not a 3.92 geared 8 speed. Typical GM comparison. Not to mention the GM truck had smaller tires, as usual. Yup, they need all the help they can get!

At the same time, the 3.55 geared Ram will suck a lot less fuel then the 6.2 with 3.73s, and it's not premium like the 6.2 needs.

A little off topic yeah, but the point is, when a company provides two or three other companies trucks to compare, they will do what it takes to make theirs shine!

Ugly truck!

Could they have put the exhaust brake closer to the driver?

@Dodgeguy65 -- We'll be doing something pretty special this summer and we're hoping to have all the one-tons and 3/4-tons represented. If all goes well, it will be our biggest "Hurt Locker style" HD road test to date. More to come.

Significantly Refreshed , gimme a break, the new Ford is also then

I really, really like this truck...except for those mirrors! Can't GM get a set of mirrors like Ford has...or at least similar?

And they could update their factory rim options more than every 7 years too!

10K lb trailer? Really GM? You make a big deal about being able to pull over 18K hitch mounted lbs and you use a trailer weighing 1400 lb less than what you say a "properly equipped" 1/2 ton Silverado can pull? Fact is if they had used any trailer near 15K lbs their truck would have been spanked by both the older Ram and Ford. A better test would have been to make all three trailers weigh what the lowest truck was rated to hitch carry. This truck will not win the next HD shootout, just like the new 1/2 truck was a middling mid pack finisher a few months ago.

Any real difference between the sierra and silverado (or colorado vs canyon)? Funny how they try to differentiate the two by releasing them at different times and doing first drives at different times. About as different as a f250 king ranch vs platinum.

I say the same thing those GM tow mirrors are ugly and Ford probably has the best.

I luv the looks of the New GMC's! Bravo GM!

@99FXD, the chassis and power train is carry over. So how can it be all-new? The F150 has a new engine, chassis, and body/interior. Though the transmission is carry over. I bet very few vehicles ever see no parts carried over from a previous model. Perhaps the Tundra did back in 2007, since the older one was a smaller truck with a smaller engine and a 4 speed.

The Sierra looks so much better than the Silverado. Nice!

Looking forward to the test this summer. I think it will be really close between all of them. That Sierra HD is a sharp looking truck.

All if the Big Three's HD's do a fine job of getting the job done! Just pick the one you like!

I do like the new Silverado/Sierra, but there is no way GM will get me to part with that much money and not offer a two tone paint! Look at the King Ranch and Long Horn... It just seems a half hearted effort to offer the Denali and High Country editions with Bells and Whistles on the interior, but the exterior has nothing to set it apart (Most of all no two tone paint options!)

My dream is coming true. I want a Sierra 2500HD, 1500 and the new Canyon sitting in my driveway. Now what color should I get. Black is too hard to maintain, white is too plain for my tastes, so maybe blue or red. Starting to really like the Sierra's better then the Silverado for front end styling. My dad always bought GMC, but I've been buying the Chevy and I think it really comes down to the dealer network that GM has. I'm much closer to a Chevy dealer and he was friends with the local GMC dealer were he lived.


Yes, pick the one you like. Seems like more people like the Ford's.

@Len, I have to agree. They're all making really good trucks.

Do you thing gm waiting for ford 2015 to bring the new dmax on the market????

Nice looking truck! Both Duramax's I have owned have been great. Even though the Sierra and Silverado are mechanical twins I like having the option of 2 different body styles. I think we can expect to see more regular updates with the new gen trucks as well.

These trucks are just ugly. Can't believe GM can't nail any design.

@Miath, It looks like 2016 model year will be the earliest that they have an updated Duramax.

That 1 ton duallie Denali sure has a big rig look to it. The snout looks better for some reason with the wider 1 ton flares.
Is looks overdone and too big with a single rear wheel set up.

I can't wait to see the full HD shootout for this summer.

If I were buying a larger truck for hauling I would buy this size truck. I currently drive a midsize truck because the size best fits my needs but if I needed more I would get an HD. All the new HDs are very capable.

Still more truck than necessary for the vast majority of drivers. Why they choose to buy something so overpowered, I don't know. About all I ever see them really used for is as a giant toy, with only about 10% of them used for real work.

Those new feminine looking headlights is what ruins the whole front end for me. On the GMT 800's and 900's, the Sierra was the more attractive design especially on the 900's, but not on these new ones. For the first time, the Silverado looks better than the Sierra. I hope GM redesigns those ugly gimmicky styled headlights in the not too distant future.

@Peter; Believe it or not, you can walk into your Chevy dealer and ask for a Sierra and as long as you can wait a couple days, they WILL get you one. That's a sale they wouldn't make if not for their location.
Vice versa is true too.

full chassis frame specifically made for a 2015 GMC Sierra 2500HD.

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