The new 2020 GMC Sierra HD AT4 is a heavy duty truck that is ready for off-roading, but it’s not ready to give up its towing capability. We tow 14,000 lbs with a Sierra HD AT4 tow see how this truck combines off-road gear with heavy towing on the highway.
2020 GMC Sierra HD
The AT4 off-road package comes on 2500 and 3500 series trucks. It adds underbody protection, Rancho shocks, mechanically locking rear axle, all terrain tires, and unique style inside and out. The AT4 does not offer any additional ground clearance, and it’s not offered as a dually.
Under the hood is an update 6.6-liter Duramax V8 turbo-diesel with the same rating as before: 445 hp and 910 lb-ft of torque. It’s mated to an all-new 10-speed Allison branded automatic transmission.
When properly equipped single rear wheel trucks are rated to tow up to 18,500 lbs for the 2500 and 21,000 lbs for the 3500.
This is precisely what we wanted to test, and the GMC provided a 14,000 lbs trailer with a surprise inside. The surprise is a 2021 GMC Canyon AT4 prototype.
Check out TFLtruck Youtube channel to the complete video.