2020 GMC Sierra 2500HD AT4 Review

2020 GMC Sierra 2500HD AT4 Review By Auto Critic Steve Hammes

Driven by cheaper fuel prices and a resurgent appetite for all things large, the truck segment is in the midst of a renaissance like never before: they’re bigger, smarter, more capable and increasingly luxurious with jaw dropping price tags.  And this one is a real monster – the all-new GMC Sierra Heavy Duty.    

I’ve driven some big trucks this year including Ram’s new 3500 dually Mega Cab but this one feels even more gargantuan.  It’s the Sierra 2500 Heavy Duty; taller and longer than its predecessor and now available in AT4 livery for a little more off-road worthiness.  You’ll need the various sidesteps, bumper steps and grab handles for this one because it’s just that large.  But that’s what you would expect from a next generation heavy duty; every adjective in the dictionary meaning MORE.        

GMC says that trailering is the most important consideration for Sierra Heavy Duty customers – this one can tow 18,500 pound, by the way, you can check the specifics for your configuration right on the door jamb – so they’ve poured a boatload of resources into cameras, apps and a multitude of other features to make pulling stuff as safe and as stress-free as possible.  

 

 

With 15 camera views including surround vision and a bed view, a rearview camera mirror, and an optional transparent trailer view camera that my tester doesn’t have and requires additional installation, every inch of this truck is covered by more eyeballs.  Furthermore, there are larger, power extendable trailering mirrors with power retract, the all-new Park Grade Hold Assist that keeps the wheels braked for an extended period of time, a diesel exhaust brake and an in-vehicle trailering app that can retain various trailer profiles and perform safety tests with that same information available through the myGMC mobile app. 

And depending upon your trailer, the app can turn on the trailer’s air conditioning or water heater, check water and holding tank levels, or monitor fuel levels for the generator — all while you’re still driving.  It does not have, however, Ford’s super easy Pro Trailer Backup Assist that does the steering for you but otherwise the breadth of trailering features here is off the charts impressive.  The bed lift-in height is also lower than before for easier 5^th wheel and gooseneck hitching.  The bigger frame allows for up to 35,500 pounds when configured as a 3500HD, regular cab, 2WD dually diesel.  Speaking of which…   

So which do you choose: The new 6.6-liter gas V8 or, or for a mere $10,000 more, this carryover 6.6L Duramax diesel? Rated at 445 horsepower and 910 pound-feet of torque it feels more alive than the new 1000 pound-foot Cummins I recently tested in the Ram.  And GMC says it now performs more efficiently thanks to this enormous grille and the hood scoop, allowing for increased cooling.  I’ve averaged 15mpg.

 

The AT4 part of this equation starts with off-road tuned Rancho shocks, skid plates and a locking rear differential.  Riding on optional 20” wheels fitted with new Goodyear Trailrunner tires, the AT4 also packs a specific Off-Road driving mode, Hill Descent Control and Hill Start Assist, a heads-up display, off-road gauges, and low speed surround vision camera.  It also possesses a bolder appearance and red recovery hooks. 

 

Furthermore the cabin receives AT4 specific upgrades such as these color accents and all-weather floor liners.  And despite its size it’s an easy going drive with surprisingly precise recirculating ball steering and a new 10-speed transmission that is smooth, reactive and beautifully matched with the diesel. The torsion bar front suspension is an interesting choice but the ride is super smooth UNTIL something upsets the body and then it’s jounce for days. 

 

   

Space is not an issue…the rear seats are bigger than some apartments.  There are also clever cubbies and the seats fold up when not needed.  And my heavily optioned tester is loaded with luxury goodies and safety tech that gives it a high-end resume yet it all just looks a bit dated and uninspired when the competition is going all-in on such matters. 

 

I love the convenient location of the wireless charge pad, huge center console, and new higher seating position that places you nearly eye-to-eye with the big rig drivers.  But this touchscreen is too small now and there’s no adaptive cruise control on 2500 models even though it looks like it exists.  The safety features are otherwise high with auto high beams, the vibrating safety alert seat, lane departure warning and automatic emergency braking.   

   

The next frontier in the pickup truck wars seems to be focused on the tailgate where cleverness has finally arrived.  This one has 6 configurations to fit a variety of needs – it’s so smart you wonder why this hasn’t happened before.

 

 

 

 

Remember those old Chevy TV spots with Howie Long taking shots at Ford for their “old guy” tailgate step?  Well, it looks like GM has come to the other side and then some.  Called the MultiPro tailgate and introduced on the Sierra 1500, it now moves up to the big boys with various ways to make your job easier. 

 

 

The price of this truck starts at $57,700 and with options checks in at a healthy $77,155 so Professional Grade doesn’t come cheaply.  But this is no doubt a very impressive ¾ ton pickup with off-road chops, huge presence and the trailering tech to match.