Car Reviews First Drives

2020 GMC Sierra 1500 Duramax First Drive: More Spice, More Flavor

Getting the recipe right will take some time, but it’s getting there

Getting the recipe right will take some time, but it’s getting there

In the high-stakes world of half-ton pickup trucks, getting your buyers the right mix of style and technology is critical. Too little, and you can taste bland; too much, and you risk indigestion. The trick, it seems, for smartest pickup makers is to offer many different features and flavors for a wide variety of customers so they can find what they like. And that seems to be exactly what GMC is trying to do with its 2020 Sierra 1500 (all new last year), which now offers an all new, all-aluminum 3.0-liter turbodiesel I-6 engine, rated at 277 horsepower at 3,750 rpm and 460 lb-ft of torque at 1,500 rpm. Both Ford and Ram have recently introduced/re-introduced their light-duty diesels into the segment; however, this new GM straight-six seems to be the most solid choice of the bunch.

We’ve already read about GM’s all new light-duty diesel in our First Drive piece on the 2020 Chevrolet Silverado 1500 Duramax, and just in case you didn’t know, the GMC Sierra 1500 shares this new engine with the Chevy Silverado 1500. In our earlier drive, we liked the engine and its performance feel, but we didn’t get to do much hauling, towing, or off-roading. This time around, with the GMC, we got to do all three.

To offer a quick technical recap, the new light-duty diesel uses an all new I-6 design for quietness and balance, utilizing an aluminum block and head setup with a variable intake manifold and state-of-the-art high-pressure fuel injection. Additionally, the engine can send cool or warm fluids to the block and head as needed, and has a variable geometry water-cooled turbocharger and stop/start technology—all mated to the new 10-speed transmission. The whole thing produces 95 percent of peak torque between 1,250 rpm and 3,000 rpm. A flat torque curve like this means more pulling power for longer periods of time, always a good thing if you happen to be using your pickup like a pickup.

How does it feel on the road? In two words, smooth and responsive. Of course, we’re guessing a lot of that has to do with the computer software integration with the new 10-speed transmission (also newly available for 2020 with the DFM 5.3-liter V-8), which never gave us any harsh shifts or hunts during our drive routes. We played quite a bit with the selectable dial settings, as well, and found each one (Sport, Touring, Off Road, and Tow/Haul) to deliver a unique feel, changing shift points, traction control settings, throttle response, and more. We ended up preferring the more controlled feel of the AT4 suspension over the cushy and floaty feel of the Denali, but you can always change the personality of this truck with the different trans select choice. No matter what you like, there’s a good amount of adjustability.

And for those who tow (especially in or near the mountains), this new engine utilizes its turbocharger to provide a healthy dose of backpressure (as an automatic exhaust brake) to control downhill speeds. Although none of the light-duty diesel engines in this segment provide for a separate exhaust brake button (as is standard on the bigger HD turbodiesel), the 3.0-liter Duramax is the only one that fully integrate this feature in its Tow/Haul setup. We felt the difference when towing an 8,000-pound (3,629-kg) box trailer down a 6-percent grade. Our vehicle held its gear, keeping a constant engine rpm to provide us a good amount of control in traffic, allowing us to work our brakes sparingly.

Although we haven’t had the chance to do any track testing with this powertrain (stay tuned for our upcoming Truck of the Year competition in the next few months), we found the acceleration feel to be impressive. During our most recent test drive in the Rocky Mountains near Jackson Hole, Wyoming (at 6,300 feet above sea level), we had both a new Denali and AT4 crew cab 4×4 with the new Duramax. Even here, we found the throttle response to be crisp and precise, but when in Sport mode, the hulking pickup actually felt nimble and quick off the line and quite comfortable diving in and out of hard corners. The GM engineers on hand told us the entire lineup of half-tons had their suspensions (both front coils and leaf rear springs) retuned for the 2020 model year, mostly due to customer feedback. The most impressive changes we experienced were on the popular AT4 package, where we noticed the Rancho monotube shocks doing a much better job dealing with higher-speed inputs. The high-speed desert wash crowd will surely be much happier with this retune.

For those who might not be familiar with the relatively new AT4 off-road package (an evolution of the earlier All Terrain package), it offers quite a few unique features that make it a strong performer in challenging terrain. When paired with the torquey performance of the Duramax engine, we’re guessing this will likely be one of the most popular setups for those who like to explore remote from the northeast to the southwest. In the name of full disclosure, GMC’s AT4 package is effectively the same as the Chevy Silverado 1500 Trail Boss, offering a uniquely tuned 2-inch suspension lift, Rancho monotube shocks, bigger wheels and 32-inch all-terrain tires, extra skid-plating, a G80 auto-locking rear diff, and a few other technology details like surround view cameras, hill descent control, and a color heads-up display that provides forward, back, and side-to-side incline readouts.

We had the chance to run a Duramax AT4 over a nasty rock-strewn course in low range and found the setup, especially with the forward and surround-view cameras, an easy no-spotter, stress-free ascent. Also available is a feature that detects the steepness of your incline when you take your foot on-then-off the brake and will hold it automatically until you touch the throttle. That hill-hold technology could prevent a lot of body damage in places like San Francisco and Seattle, too. During this section of our test, we quickly found out  cameras are only as good as their ability to shed mud and dirty water. It would have been nice to have a quick squirter nozzle (at least on the front and rear lenses) to give us an idea of what to expect when we open the doors.

Clearly, the off-road portion of our test was the most fun, but empty and loaded runs through the mountain roads connecting the part of Wyoming and Idaho along the Snake River gave us a chance to let the horses run. We got a pretty good idea that this setup is more than capable of multi-tasking, a particularly important detail for many new-truck buyers. As to how this package (Denali or AT4 Duramax) will hold up against the Ram and Ford offerings, we can’t be exactly sure, given our altitude driving and limited time with the trucks. But we can say GM engineers have done a stellar job seamlessly integrating the engine’s power with the super-smart, selectable 10-speed transmission. We never felt a hard shift or clumsy hunt for the next gear no matter what the situation, which we’ve experienced in both of its competitors.

Since we’re talking about how this new light-duty pickup compares with the competition, we simply have to note there are still relatively few (if any) changes to the interior of the different trim levels for the 2020 model year, Duramax or not. So if you were hoping for GMC to up its game (even ahead of Chevy) for this new powertrain configuration, you’ll have to wait a little longer. Both top-of-the-line Ram and Ford light-duties (and even a few of their midlevel trims) seem to be doing a better job with material choices, layout, and design. That said, we’re willing to give both Chevy and GMC a little more time. Still, GMC is doing well with exclusive technologies like the clever Multi Pro Tailgate and almost indestructible Carbon Pro composite bed, but you can expect more attention-getting features to come.

2020 Duramax Sierra 1500s should be getting to dealerships now and will be priced identically to the 6.2-liter gas V-8 engine, or a $2,495 USD option over the 5.3-liter DFM gas V-8, and a $3,890 USD premium over the standard (in some cases) 2.7-liter turbo I-4. The Duramax will eventually be available across the lineup in all configurations, with the exception of the entry-level Sierra trim package for now.