There is a lot more to the updated 2027 GMC Sierra HD than the hot new 8.3L Duramax V8 turbo-diesel engine. This 2027 model has more power and torque, but almost every other chassis component has to be updated and upgraded to keep up. Roman goes to GM’s proving grounds in Michigan to get a close look and get a complete engineering deep dive. Let’s dig in!
The new 8.3L “mongoose” L6P engine makes most of the headlines. It’s rated at 555 hp @ 2,500 rpm and 1,230 lb-ft of torque @ 1,400 rpm. GM engineers needed to beef up the 10-speed Allison-branded automatic transmission, the frame, suspension, brakes, and the steering system to keep up with the new torque-monster.
In this video, we also learn the GM increased the size of the DEF tank from 7 gallons to 9 gallons. The diesel tank remains at 36 gallons. Could it be that the new engine requires more DEF than before? We don’t know this yet. There are rumors that the new diesel engine is actually more efficient than the outgoing smaller 6.6L Duramax. We will have to test this in Colorado very soon.
GM says these new HD pickup trucks (2027 Chevy Silverado HD and the 2027 GMC Sierra HD) will go on sale starting this year.
Check out the video for all of the details.
