2015 GMC Sierra

By G.R. Whale January 14, 2015

The GMC Sierra delivers stout towing and hauling ability, a quiet cabin, and distinctive styling. GMC Sierra is built on the same platform and shares many mechanical pieces and body panels with the Chevrolet Silverado. Front-end styling and some details vary, but if you ever needed service either dealership could do it.

Sierra was redesigned for the 2014 model, and the 2015 Sierra gets some noteworthy updates. All 2015 Sierra models offer a spray-in bedliner with molded GMC logo, OnStar and 4G LTE with built-in wi-fi, and tow ratings adhere to SAE J2807 standards. New towing mirrors have LED guide lights for reversing, and IntelliLInk adds text messaging alert and Siri eyes free. The 6.2-liter V8 option now comes with an 8-speed automatic transmission. And the 2015 Sierra Denali comes with magnetic ride control.

The GMC Sierra 1500 offers a choice of three cabs and three bed lengths: Regular Cab standard and long bed, Double Cab standard, and Crew Cab standard or short bed. Nearly all offer 2WD or 4WD.

Three engines include a V6 and two V8s, all favoring torque over horsepower and sharing the same fuel-saving technologies often reserved for optional engines. The V6 has the highest torque of any full-size base V6, and the 6.2-liter V8 is the most powerful engine in a light-duty full-size pickup. The smaller engines use a 6-speed automatic and can run E85; the 6.2 uses an 8-speed.

Sierra trim levels vary from work truck with wind-up windows to Denali in stitched perforated leather trimmed with genuine aluminum. Front rows offer seats for two or three, rear seats have three belts, and multiple child-seat anchors, but we don’t recommend them for three adults.

Beyond the appearance relative a Silverado, the Sierra offers LED front position lights and Elevation and Carbon Edition specials Silverado does not. Sierra Denali has a unique instrument panel and magnetic ride control not offered on Silverado. Sierra has a higher level of standard equipment. GMC’s Pro Grade plan covers some routine maintenance for the first two years or 24,000 miles.

Sierra competes against the Ford F-150, Ram 1500, Nissan Titan, Toyota Tundra and Chevrolet Silverado. If Sierra is too small, try GMC Sierra HD; if it’s too big, try GMC Canyon.

Model Lineup

The 2015 GMC Sierra offers three engine choices: a 285-hp 4.3-liter V6, 355-hp 5.3-liter V8 and a 420-hp 6.2-liter V8. The 4.3 and 5.3 run on regular unleaded or E85 (power increases, mpg decreases) and come with a 6-speed automatic. The 6.2 available only on four-door cabs recommends but does not require premium unleaded, and comes with an 8-speed automatic.

Regular Cabs come with a standard bed (6-foot, 6-inch) or a long bed (8-foot), seating for two-three, in Sierra and SLE trim. Double Cabs have two rows of seats and four doors with roll-down windows. They come with a standard bed, in Sierra, SLE, and SLT trim. Crew Cabs have larger rear doors and cabin space than Double Cab. Crew Cabs come with a short (5-foot, 8-inch) or standard bed, in Sierra to Denali trim levels.

Sierra ($26,605) comes standard with vinyl 40/20/40 front seating surfaces, air conditioning, full instrumentation, tilt steering wheel, corner step bumper, AM/FM stereo with USB, aux and SD inputs, cruise control, trip computer, 17-inch steel wheels, power door locks, locking tailgate, power windows on four-doors, chrome grille surround and bumpers, and a two-year maintenance program. Options: 5.3-liter V8, rearview camera, trailering pack, power windows, block heater, ATF cooler, integrated trailer brake controller, side steps, bed accessories, heated power mirrors, all-terrain tires, Bluetooth, OnStar with 4G LTE with wi-fi hotspot (3-month trial period), SiriusXM radio and a snow-plow package for 4WD regular cabs.

Sierra SLE ($32,935) upgrades with cloth upholstery, leather-wrapped steering wheel, aluminum wheels, body-color door handles and side moldings, LED box lighting, EZ-lift and lower tailgate, deep-tint glass, heated power mirrors, 8-inch touch-screen with IntelliLink, CD, SiriusXM and HD radio, OnStar with 4G LTE, Bluetooth, carpet, color driver information display, lit visor mirrors, power windows, rear camera, remote keyless entry and steering wheel audio controls. Four-doors also get body-color mirrors, folding rear seats and rear wheelhouse liners. SLE options include the Z71 off-road package, All Terrain package, 18 and 20-inch wheels, navigation, heated leather seats, driver alert package, remote start, bucket seats, security system and Carbon and Texas special edition models.

Sierra SLT ($40,240) adds leather seat trim, power heated front seats, telescoping steering wheel, dual-zone climate control, 18-inch polished aluminum wheels, power-adjustable pedals, chrome exterior trim, fog lamps, LED daytime running lights, power-folding mirrors, trailering package, 110-VAC outlet, remote start, and universal home remote. 4WD models get Autotrac. SLT options include the 5.3 and 6.2-liter engines (the latter with active noise cancellation), heated steering wheel, heated/cooled leather bucket seats, Bose sound system, the All Terrain pack, and some safety and mechanical upgrades.

Sierra Denali ($49,005) upgrades further with unique leather and trim inside and out, a unique instrument panel with 8-inch display, 5.3-liter V8, heated steering wheel, Bose sound system, power sliding rear window with defrost, locking differential, magnetic ride control shock absorbers, spray-in bed liner, machined-face 20-inch aluminum wheels, navigation and front/rear park assist. Denali options are limited to the 6.2 V8, moonroof, driver alert package, Z71 pack, rear entertainment package, floor mats, bed accessories and seven 22-inch wheel designs.

Safety features include dual front airbags, front side airbags, side curftain airbags front and rear, StabiliTrak electronic stability control and tire-pressure monitoring. OnStar and its suite of functions are available on every Sierra.

Walkaround

GMC’s three sizes of pickups look more alike than any other brands’ lineup. As such you may easily mistake a Sierra 1500 for a Sierra HD or a Canyon if there’s nothing around for scale.

Redesigned for 2014, the Sierra looks bigger than the previous-generation, but it isn’t. Despite its angular, blocky profile, the front end is more aerodynamic and if you look around carefully you’ll find little bits and pieces all around to lower aero drag even further.

A prominent ruby-red GMC logo graces every grille but trims are otherwise differentiated, yielding more chrome on and around the three wave grille. SLT gets LED position lights around the headlights, while Denali gets finer, rectangular lattice-work grille.

Wheel openings are GM’s recent-tradition square, with plenty of room in the fender wells; the fender bulges covering the wheels reach almost to the top of their respective panels. Doors and glass are clean and sleek, and the front door is smaller than pre-2014 because the mid-cab pillar was moved forward four inches. That makes easier entry to the rear seat and allows the Double Cab to use conventional doors; a quieter and more rigid cab, and rear-seat access independent of the front are primary benefits.

Crisp angular lines continue all the way back, ending in a bumper with steps in each corner (and a hand-hold in the bed rail). Tailgates lock and on most lower and lift easily. Trailer plugs are convenient in the illuminated license plate well.

Various bed accessories are available, including LED lighting inside it, cargo retention systems, spray-in or drop-in liners, and retracting bed side steps.

No Sierra is taller than 6-feet, 2.1 inches. Unlike many pickups, Sierra 4WD models are about the same ride height as 2WD. That could prove handy in urban parking garages or over-hung trails, or when climbing in and out or loading or unloading.

Interior Features

Even on the base truck, long-time pickup owners will first notice the quiet inside. Regardless of size or trim, the GMC Sierra is comfortable and well thought-out. On top trims you may have more USB ports and wi-fi device support than seatbelts.

You might dismiss the Sierra cabin as a Silverado with different badges and red lighting rather than aqua hue. To a great extent you’d be right, but the GMC gets more detail touches on lower trim than does the Silverado and the Denali has a unique instrument panel.

Consider the big dash in three segments. Left is the gauge pod with trailer brake, lighting, 2/4WD switching and vent outboard, wipers on the stalk. In the center are all other operating controls and touch-screen, with dual gloveboxes ahead of the passenger. The broad armrest/storage bin is centered between the front seats, but everything forward of it (gauges, steering wheel, center stack and console) is offset about an inch to the right. While that may tease driver eyes toward the middle of the lane, it gives the driver more right knee room and gives passengers an easier reach to climate and audio.

Manual-adjust steering wheels use one lever for tilt, one for telescope; power-adjust wheels use a single control. We like the brake controller left, where you might be looking in the mirror for trailer lockup, others said the controls out there crowd the wheel and gauges.

Numbered analog gauges are as good as those on any pickup. Further data, including transmission fluid temperature, brake controls, fuel economy comes up in the display between the gauges, using wheel-spoke thumb switches. On Denali, only the tach and speedometer are analog, the configurable 8-inch screen between showing graphic representations of gauges that automatically substitute transmission fluid temp for volts when you engage tow/haul mode.

Touch-screens work easily regardless of features, and there are plenty. Between IntelliLink and OnStar you could ask a lot of your truck without being in it, and now OnStar offers 4G LTE for a Wi-Fi hotspot capable of dealing with up to 7 devices within 50 feet. Verify rates with your dealer, and note we were driving another brand with 4G LTE and a view of Silicon Valley but it didn’t work because there was no coverage. IntelliLink adds text messaging and Siri eyes free for 2015, and bench seat models get a USB port in the glovebox; loaded trucks will have at least 5 USB ports, SD slot, and DC and AC power.

We recommend you explore any telematics system parked, then see which features are disabled with the truck in motion: Voice-recognition may be handier than you think.

The switch bank below (bed light, park sensors, pedals, etc) is made to fit. There are never any blanks that suggest you missed a feature or leave a spot to add your own accessory switch.

Cabin storage includes dual gloveboxes, two or three bins in each door, and center console open in front and beneath the armrest or on the 40/20/40 front seat a fold-down backrest-becomes-armrest, and more space beneath the seat cushion. That’s all better for storage than for center seat comfort.

Bench or bucket we found all outboard front seats quite comfortable. Rear seats in the Double Cab are better for kids or smaller adults. The Crew Cab has nearly as much room in back as in front but there’s no center headrest and the outboard headrests were inadequate for a couple of 5-foot, 9-inch passengers. Most rear seats fold up for indoor cargo or hounds prone to sliding on seats.

Heated front seats can be combined with cloth upholstery, heated/cooled on leather only. Because it’s so quiet you can hear the cooler fan if you don’t have the stereo jamming. The heated steering wheel switch is thoughtfully in plain sight on the wheel spoke, not buried on the dash or a menu somewhere.

Outward visibility is adequate. Pillars are large but reasonably well forward, bodywork edges somewhat defined, rearview camera available where not standard and the driver’s mirror has a built-in wide-angle spot. Taller drivers noted a low windshield top, optimists preferred it for driving into the sun. New towing mirrors have LED guide lights for backing in unfamiliar areas.

Sierra also offers a driver alert package for impending frontal collision or lane-departure warning, both defeatable (the former for off-high travel or gridlock, the latter for construction zones or wacky striping). Warnings include audible, visual and tactile as the seat buzzes.

Driving Impressions

Sierra handles half-ton pickup and second-car jobs with almost equal ease. It feels comfortable, solid and quiet.

Every Sierra save the Denali comes with a 4.3-liter V6 engine standard. Unlike domestic brand-name competitors this is a truck engine that stresses torque rather than high-revving horsepower, and as one competitor often advertised, torque is what matters in pickup trucks.

The 285-hp 4.3 makes 305 lb-ft of torque, clearly superior to F-150’s base 3.5 (255 lb-ft) and Ram’s 3.6 (278 lb-ft) although the Ram gets more power multiplication from its 8-speed automatic. The GMC 4.3 also gets the same fuel-saving measures applied to its bigger engines, a first for a base pickup in our recollection. EPA ratings are 18/24 (2WD) and 17/22 (4WD). We found the 4.3 sufficient to pull a tandem-axle travel trailer estimated at 5500 pounds behind a 2WD Crew cab with no trouble, while making less noise than the rev-requiring competitor V6s and a very quiet idle. Buyers whose budget precludes a bigger, thirstier engine should not be disappointed.

A 5.3-liter V8 is around $1000 more, upping horsepower to 355, torque to 380 lb-ft and it’s a bit smoother than the V6. EPA ratings drop slightly to 16/23 (16/22 4WD) but we guarantee if you regularly use 70 extra horses it’ll cost more than 1 mpg. The V8 doesn’t add payload capacity but it could increase towing capacity by 5,500 pounds. Our GM sources note that of 1500-series owners that do tow, the average trailer is 3500 pounds.

Both the 4.3 and 5.3 switch to four-cylinder operation when power’s not needed, automatically. It appears the V6 runs as a four more than the V8 does; 2/3 of the V6 is more displacement than half of the V8. Unless the majority of your driving is level highway cruising, we’d get the highest-number axle ratio available. Both engines are also E85 capable; on E85 they make about 10-percent more power but the mileage percentage drop approaches three times that.

GM’s proven 6-speed automatic with tow/haul mode works as expected, and comparably to Ford and Toyota’s 6-speeds; we’d label the Ram’s 8-speed more advanced.

However, for 2015 the top GMC engine, a 420-hp 6.2-liter V8 that prefers premium unleaded and includes active noise cancellation, comes paired to an 8-speed automatic. This allows taller axle ratios for highway economy, think 60 mph at just 1350 rpm, but also improved acceleration performance and a more-effortless in-town drive. It also makes it much easier to back a trailer uphill and control downhill speed using engine braking.

The 6.2 is rated for trailers to 12,000 pounds; that a 2WD four-door base-trim truck with tow package and driver. At post, that’s 200 pounds less than F-150’s top rating and well ahead of other competitors content to not contest the half-ton towing war. At this level the Sierra’s power-to-weight ratio is ahead of the F-150. Were we towing five tons or more regularly we’d step up to a ¾-ton truck, and every Sierra should handle a 3500-pound trailer with the truck fully loaded. The integrated brake controller option is handy for any trailer using electric brakes, warranted with the truck, and may help resale value.

Payload (includes people, cargo, and trailer tongue weight) ranges from 1660 to 2270 pounds on base trim trucks (deduct a few hundred for lots of options), a 4WD Double Cab the highest rated. Unlike competitors, the top payload and tow rating are available on the same truck. These loads are typical for the class but four of the forty-odd permutations of the F-150 are rated to carry 3,000-plus pounds; previously only dual-rear wheel heavy-duty pickups have been rated to carry 70 percent (or more) of their own weight.

On the road Sierra is quiet and stable. The feel from steering assist to ride is substantial, not necessarily a bad thing. Electric-assist steering maneuvers better than hydraulic assist and turns just as tight despite a wider track for crisper response. Like any pickup it rides better with a little weight on board, and cruising it is quiet, almost serene inside.

For 2015 the Denali model gets magnetic ride control, employing a shock-absorber design used by the likes of Cadillac, Corvette and Ferrari that adjusts damping rates in five milliseconds to deliver the best combination of ride and control. We noticed the biggest difference on washboard, rippled surfaces, but also noted a less-fancy Crew cab on 18-inch tires covered decent roads just as comfortably.

The Z71 off-road package is available on most Sierra, and historically has given the best balance of ride comfort and handling, whether on pavement or off. Trail performance is good, with many sporting a locking rear differential, and the economy-inspired front air dam will scuff plenty.

Summary, Prices, Specs

The GMC Sierra offers plenty of power choices, realistic load and excellent towing ratings, and models spanning less than $30,000 to more than $60,000 mean one should fit your needs, whether you need a tow rig, work truck, or merely a second car with four doors and a 6.5-foot bed that fits in a standard garage.

NewCarTestDrive.com correspondent G.R. Whale reported from Los Angeles and San Antonio.