GM Reportedly Bringing New Powertrains To Its Heavy-Duty Trucks
When GM unveiled the updated GMC Sierra and Chevrolet Silverado earlier this year. The duo brought new styling, technology, and powertrains to the company’s bread-and-butter pickup models. Their heavy-duty counterparts have so far stayed hidden in the shadows. Even so, they are expected to follow largely the same script.
A new report, however, suggests GM might act before those new models arrive. The automaker could use the current-generation heavy-duty pickups to launch all-new powertrains. The move would be a possible attempt to make the trucks more desirable to heavy-duty buyers.
GM Reportedly Flipping The Script
Typically, we see new powertrains appear along with a new or revamped vehicle. But this new report from GM Authority suggests otherwise. The company will use the 2027 model year to debut the new powertrains. The site said it caught wind of this from “sources familiar with the matter.” The report alleges GM will replace the naturally aspirated 6.6-liter L8T V8 with the L8S. The L8S would keep the same displacement but top the L8T’s 401 horsepower.
The second new powertrain reportedly on deck is an all-new L6P Duramax diesel. It would replace the current L5P engine. That engine also displaces 6.6 liters. GM has not said what changes the new diesel will bring or whether it will make more power. For context, the L5P currently in service makes 470 horsepower and 975 lb-ft of torque.
Report Comes As GM Pushes To Increase Engine Production
The report also lands as GM expands its combustion engine production. Slumping demand for EVs has proven to be a big motivator. The company has committed $920 million to boost Duramax diesel production at its plant in Brookville, Ohio.
GM, for its part, chose not to comment on the validity of the report. If GM is indeed pursuing this plan, the new engines would do two things. First, they would make the current heavy-duty trucks better. They would also let GM test the engines in the real world before they join the updated heavy-duty lineup.
New Batch Of Rumors Has Precedent
The rumors also follow GM already launching several new V8 engines this year. The Chevrolet Corvette gained the all-new 6.7-liter LS6 small-block V8 for 2027. That engine makes 535 horsepower and 520 lb-ft of torque. Both figures top the 2026 model. The extra muscle helps the Corvette stave off its rivals.
Meanwhile, the Chevrolet Silverado and GMC Sierra 1500 are debuting two new V8s of their own for 2027. The new 5.7-liter V8 replaces the aging 5.3-liter V8. An all-new 6.6-liter V8 will replace the 6.2-liter V8 too. That swap also removes a headache for GM. The outgoing engine had become infamous for costly recalls.
When Will We See The Next-Generation Heavy-Duty Truck Models?
The missing piece has been when GM will reveal the next-generation heavy-duty versions of the Silverado and Sierra. We now have it on good authority that they will appear later this month. That timing would put the next-generation HDs in front of buyers much sooner than expected. Many had bet on a far more drawn-out rollout for GM’s heavy-duty lineup.
Even with an early arrival, the current-generation trucks are not going anywhere just yet. Their rumored new powertrains would let GM keep the segment covered while the next-generation models settle in. That would give the automaker a running start heading into next year.