- Enormous range of options and styles
- Strong turbodiesel V-8
- Comfortable interior
- Confident towing ability
- Price skyrockets with options
- No crash test data
- No fuel economy data
- Do you really need 910 pound-feet of torque?
The GMC Sierra HD might be our favorite large trailer hauler, but at this price it should be.
The 2017 GMC Sierra Heavy Duty truck lineup builds on the basic half-ton Sierra with a stronger frame, beefier axles, and the ability to tow significantly more thanks to its new-for-2017 optional turbodiesel engine.
We've rated the Sierra 2500HD, the most popular version of the automaker's heavy-duty trucks, as a 7.0 overall thanks to its high level of refinement and customizability as well as the strength of its smooth and quiet turbodiesel.
The Sierra HD is functionally identical to the Chevrolet Silverado HD, although GMC says it sells a higher percentage of its trucks directly to consumers rather than fleet operators and it offers a wider range of models—from work-oriented SL up to downright luxurious Denali.
That said, we haven't spent much time in the gas-powered version of the Sierra HD and we have limited experience behind the wheel of the more robust 3500HD.
GMC Sierra HD styling and performance
For the most part, the Sierra HD mirrors its 1500 siblings, although it sits a little higher off the ground and has a slightly taller front fascia. Diesel models stand out for their functional hood scoops that supply cold air directly into the intake to improve performance and reduce engine temperatures. The Sierra HD is available in several body configurations, including regular, extended, and crew cab models with either 6'6 or 8' bed lengths.
On all, a 6.0-liter gasoline V-8 rated at 360 horsepower and 380 pound-feet of torque is standard and it's mated exclusively to a 6-speed automatic with a tow/haul mode. A 6.6-liter turbodiesel V-8 is on the options list and it's rated at 445 horsepower and an astounding 910 pound-feet of torque. Amazingly, GM's turbodiesel is actually outmatched by Ford's 925 pound-foot unit.
All models are available with either rear- or four-wheel drive; the latter is an off-pavement only setup without an automatic mode like on the Sierra 1500. A leaf-spring rear axle and independent front setup is on all, a typical setup for a large pickup.
More than half of all Sierra HDs are ordered with the pricey, but strong diesel; that share escalates with higher-spec models to the point that 90 percent of all Denalis are diesels.
We've only spent time in the turbodiesel. It's almost silent at idle thanks to numerous mechanical enhancements for 2017. Acceleration is robust; GMC quotes a 7.1 second 0-60 sprint for the crew cab with four-wheel drive, a figure that would have been impressive for a sports car just a few years ago. Diesel models also include an exhaust brake so effective that it can help the truck maintain a comfortable highway speed even down an 8 percent grade.
As we've come to expect from big pickups, the Sierra HD's steering isn't exactly a model of precision and it requires more corrections at high speeds than a half-ton, but extensive sound deadening helps make this truck a terrific long-distance cruiser. We only wish that its available adaptive cruise control was bolstered by an automatic emergency braking system.
Most owners will want to tow, and to that end the Sierra HD acquits itself well. Crew cab, short bed 2500HDs with four-wheel drive represent the bulk of all sales and they're rated at up to 13,000 pounds trailer capacity (or 14,800 when fitted with a fifth wheel setup). That's enough for most travel trailers or car haulers, but what's most impressive is the confidence with which the Sierra can tug a load.
GMC Sierra HD comfort and features
Sierra HDs mirror their half-ton siblings inside, which means they have what's arguably the nicest interior ever put into a full-size pickup. Work-oriented SLs feel predictably service-oriented inside with lots of hard plastic and a relative dearth of features given their sticker prices, but SLE and higher grades become increasingly comfortable and luxurious.
The range-topping Denali accounts for about half of all Sierra HDs sold, something that's especially impressive when you figure a loaded-up one tops $75,000 with options. They're not quite as luxurious as their price tag might suggest, but so the SLT may make the most sense. It's several thousand less but still boasts easy-to-clean leather trim, a Bose audio system, and a terrific available navigation system.
The Sierra HD's front seats are road-trip comfortable with a wide range of adjustment and modest bolstering. There's plenty of stretch-out leg room in row two on crew cabs (and a bit less on extended cabs), but the seat back itself is not adjustable and is rather upright.
No version of the Sierra HD has been crash-tested by either the IIHS or the NHTSA and, given their weight, they aren't tested for fuel economy either. On a gentle road trip in a 2500HD with the optional diesel engine, we saw nearly 20 mpg, but that figure would plummet with a trailer attached.