August 17, 2022

Someone who had access to GM Canada’s dealer site leaked information about the upcoming 3.0L Duramax I-6 available in the 2019 GMC Sierra 1500 and its Chevrolet Silverado 1500 sibling. Take this data with a grain of salt, as GM has yet to officially announce the all-new Duramax variant’s power, towing, and fuel economy ratings.

As leaked by The Fast Lane Truck, the turbodiesel engine will produce 282 hp and 450 lb-ft of torque. Mated to a 10-speed automatic transmission, the engine achieves 28 mpg on the highway, according to the leaked docs. Furthermore, the turbodiesel will reportedly be capable of towing 7,800 pounds.

Some of those numbers sound just a bit fishy to us, primarily the engine’s towing rating. The same leaked document claims a Sierra equipped with the base carryover 4.3L V-6 can tow 7,700 pounds, meaning the diesel’s 145 extra lb-ft are tasked with towing just 100 extra pounds in total. And the transmission isn’t the limiting factor, as the equally torquey 6.2L V-8 mated to a likely identical 10-speed transmission is able to lug 12,200 pounds.

In comparison, a Power Stroke V-6–equipped 2019 Ford F-150 can tow up to 11,400 pounds, while the outgoing 2018 Ram 1500’s EcoDiesel V-6 can tow up to 9,350 pounds (the 2019 Ram 1500’s EcoDiesel will be a late-availability option, so we’re not sure what it can tow yet). Given the GMC’s alleged power ratings (up 32 hp and 10 lb-ft over the Ford and 42 hp and 30 lb-ft over the outgoing Ram), we’re not sure why the documents claim such a low towing capacity.

It could be a typographical error or it could be representative of a specific trim level, not a maximum engine rating—for example, certain configurations of the 2018 Ram 1500 EcoDiesel are rated to tow just 7,760 pounds. Furthermore, the information is reportedly from a GM Canada property, meaning it could represent a regional difference that won’t apply to the U.S. So we’ll wait for official confirmation from General Motors before we make any vast assumptions.

The GMC Sierra AT4 already performs well on off-road terrain straight off the dealer lot. GMC has now introduced a special Off-Road Performance Package available for the truck to make it better.

The AT4 Off-Road Performance Package comes with a 6.2L V-8 engine mated to a 10-speed automatic transmission. This combination delivers up to 435 hp and 469 lb-ft of torque. For those keeping track, that’s an increase of 15 additional horsepower over the standard model. The package also adds a Cat-Back performance exhaust system and performance air intake. The truck is also upgraded with Goodyear Wrangler DuraTrac tires on 18-inch wheels.

“The 2019 GMC Sierra AT4 debuted all-new, purposeful technologies for the premium truck segment and the new Off-Road Performance Package takes it a step farther,” said Duncan Aldred, vice president of Global GMC. He continued, “It offers optimized performance, both on- and off-road.”

Off-road features already standard on the AT4 include a 2-inch factory-installed suspension lift, four-wheel drive with a two-speed transfer case with locking rear differential, and skidplates. The Sierra AT4 also comes with a traction control system and hill descent control. For a smoother ride, the truck is equipped with off-road–tuned Rancho monotube shock absorbers.

The Off-Road Performance Package upgrade is priced at $4,940.


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