An off-road test drive of the 2024 GMC Sierra 2500HD AT4X AEV. ... My tester had the 6.6-liter Duramax turbodiesel V8, which makes an impressive 470 horses and a monumental 975 lb-ft of torque. ...

Looking at pictures of the Overland Expo’s GMC Sierra 2500 HD AT4X Ultimate Build, it looks big, but it doesn’t look as big as it is when you’re in front of it. Before all the upgrades ...