GMC solely sells the AT4X with a single powertrain, a 6.2-liter V8 related to a 10-speed computerized transmission. That is our favourite upgraded engine/transmission mixture within the full-size section, besting each Ford’s 3.5-liter twin-turbocharged EcoBoost V6 and Ram’s 5.7-liter Hemi V8. With 420 horsepower and 460 lb-ft of torque, it is extra highly effective than its rivals (excluding the Raptor) and despite the fact that the Sierra makes use of the identical transmission because the F-150, the GMC is far smoother because of superior tuning.
Whereas it might probably’t match the Raptor or TRX on uncooked pace, it might probably outperform each on functionality. The Sierra AT4X can tow 8,900 kilos, 700 lbs greater than the Raptor, and 800 lbs greater than the TRX. It additionally boasts a 1,420-pound payload capability, greater than the Ford and Ram. We solely want GMC supplied the AT4X with its 3.0-liter Duramax diesel, because the V8’s gas financial system figures are simply common (14/18/16 mpg metropolis/freeway/mixed).