Most GMC Sierra shoppers will lean to one of its new V-8s for stronger performance and better towing, but the completely reworked V-6 deserves more attention than ever. It's no longer a penalty piece for utility trucks and fleets: it's an honest alternative to the V-8 for drivers that are honest about how often they tow and haul.
Today's full-size trucks deliver the kinds of payload, acceleration, and towing that heavy-duty trucks did just a couple of decades ago. Recalibrating the powertrain needs of truck drivers was inevitable, and this year it happens in the Sierra. The rejiggered powertrain lineup has dropped some of the former stragglers, leaving behind a trio of powerplants that hit all the benchmarks of the class.
The base engine is a 4.3-liter V-6, but don't hold any grudges with the past Vortec engines of the same name. This one's a natural fit for a lighter-duty full-size truck, anything not pressed to tow more than a few thousand pounds. Without the classic V-6 burr on full throttle, it could be mistaken for a small-displacement V-8, given the low-end torque. In all, it's rated at 285 horsepower and 305 pound-feet of torque, which we'd peg at a 0-60 mph time of about 8.0-8.5 seconds, with a smartly-geared six-speed automatic running shift plays. It's efficient--direct injection and cylinder deactivation are new--are said to boost fuel economy though EPA numbers haven't been released. And towing is up: the V-6 Sierra tows up to 7,200 pounds, a quarter-ton more than the F-150 V-6 and 700 pounds more than the best Ram V-6.
If you really do tow 5000 pounds or more on a regular basis, and don't mind a couple miles per gallon in gas-mileage penalties and a minimal $895 option price, GM's 5.3-liter V-8 is the next step on the Sierra ladder. It's a muscular powerplant, good for 355 hp and 383 pound-feet of torque, and is coupled to the same sweet six-speed automatic. In the optimum configuration, this team can tow up to 11,500 pounds, and best-case scenario, that rippling exhaust note is backed by a 23-mpg EPA highway rating, thanks again to cylinder deactivation and direct injection.
Later this year, the Sierra Denali sidles into the lineup, bringing with it an optional 6.2-liter V-8 that'll also be offered in the SLT model. The big eight sports 420 hp and 450 pound-feet of torque according to early estimates, which translates into unknown gas mileage but adds 500 pounds to the tow rating, for a class-leading 12,000-pound tow capacity, according to GMC.
All three engines connect to the same six-speed, with a choice of rear-wheel drive or shift-on-the-fly four-wheel drive. The transmission has cruise-grade braking factored into its programming; it downshifts early to assist slowing a trailer. It also has a tow/haul mode and tap-shift controls on the shift lever for direct control, helpful when pulling a trailer and modulating power more directly to merge into traffic or to steam up grades. The transmission gives up a couple of gears to the eight-speed unit in some Rams, but it's not missed much; an eight-speed would net better highway economy, but this six-speed has ideally spaced gears and a mellow shift quality that's long been one of GM's points of pride.
Ride and handling
All Sierras carry over a reworked version of the previous truck's strut front and leaf-spring rear suspension. The steering rack is new, and electric, and specially designed brakes with long-life rotors are new for 2014.
The combination nets the Sierra some large gains in responsiveness, minor ones in ride. Not quite as smooth and composed as an air-suspended Ram, the Sierra's more progressive springs front and back have become a little more absorbent, over what already was a fairly good ride. It's the steering that pays big dividends: it's quick and pretty crisp, as true to scale as the Ram's, not as overtly hefty as the F-150's. Monotube shocks come later this year on All-Terrain Sierras.
Electric steering enables more features that give the Sierra a stable, planted feel even with a few thousand extra pounds depending on it. We spent an afternoon learning some finer points of trailering with the 2014 Sierra, experimenting with Tow/Haul and tap-shifts, and engaging trailer-sway mode. We also fine-tuned the trailer-brake controller fitted on our test vehicle to accommodate a 4,500-pound Airstream and took to a short slalom and cornering course before hitting California's Highway 101. The Sierra took it all into stride, composed from highway entry to exit. The biggest issue we faced, other than narrowed lanes under construction, was a state limit on trailer speed of 55 mph--it felt stable at least 10 mph beyond that.Later this year, the Sierra All-Terrain adds some undergear to this setup. It gets a Z71 off-road suspension, monotube Rancho shocks, recovery hooks, a transfer-case shield, hill descent control, an auto-locking rear differential, and special wheels and tires. It's a bundle that's also offered on the Denali. We'll bring you more on both of those editions later this year.