GMC's Sierra AT4 2500 is an exceptional high-tech pickup with HD abilities

If heavy duty towing, construction duties, snowplowing or off-roading are some tasks on your truck shopping menu, you need to check out GMC’s new Sierra 2500 4WD AT4 Crew Cab pickup. 

Offered in Sierra, SLE, SLT, AT4 (tested) and top-shelf Denali trim models, and in long and short bed, Sierra 2500 gets its grunt from two powertrain choices. There’s a 6.6L, 401-hp and 464 lb/ft of torque V8 that couples to a 6-speed automatic transmission, and a 6.6L, turbodiesel V8 with 445-hp and a whopping 910 lb/ft of torque that couples to a 10-speed Allison automatic transmission. 

We tested the latter in the AT4 Crew Cab and it certainly has mucho grunt. It was independently 0-60 tested at 19.9 seconds when towing an 18,000-pound trailer. Sierra HD is tow rated for 20,000 pounds with a conventional hitch. Mighty impressive. And it does its work ever so quietly. Diesel rattle is non-existent at cruise speed, and otherwise, with an open window. The diesel powertrain also comes with an Integrated Engine Exhaust Brake (“Jake Brake” where engine backpressure is used to control downhill speed thereby saving the brakes). It also has auto start/stop engine technology. 

If you have a lengthy camper, horse or heavy equipment trailer to tow, there’s a gooseneck fifth-wheel option where the cargo bed has factory stamped bed holes with caps for the fifth wheel cradle. It’s tow rated for 35,500 pounds. 

When towing, Sierra offers its ProGrade Towing Package that uses up to 15 camera views to see the bed, trailer hitch, trailer sides, trailer rear end, transparent view to see through the trailer, even inside the trailer as the remote camera can be positioned anywhere on the truck/trailer. And with the myGMC mobile app, the iN-Command system can monitor and control a number of features remotely. This is truly a high-tech heavy-duty pickup. Offered too is trailer sway control, hill start assist and hill descent control and more. 

There’s so much to say and so many neat features about the Sierra, we’ll start with the off-road oriented AT4 we had the pleasure to test. 

Sierra AT4 is off-road outfitted with a 2-inch suspension lift and Rancho shocks, 4WD with two-speed transfer case and traction-select off-road mode, automatic locking rear differential, skid plates, front mounted red recovery hooks, and 19-inch tires (20s are optional). 

Sierra’s most interesting feature is its unique 6-position Multi-Pro tailgate that is standard on the AT4. GMC’s TV ads, that you must have seen by now, show its various positions and it goes five up on Ford’s tailgate with its pull-out tailgate step and pull-up assist bar. The only concern with the MultiPro is if the truck is backed into something or another truck (like a tractor trailer cab) rear-ends it, as it could be a costly repair or replacement. 

Upon a low 17-inch step into the cabin from the powered running boards, you’re treated to living room comforts. Dark grey perforated and heated leather seats with Kalahari tan inserts and stitching make a rough terrain ride, softer. 

An 8-inch touchscreen with voice control offers the gamut of audio, rearview camera with five selectable views, 4G Wi-Fi connectivity, OnStar, apps and much more. Its operation requires a serious study of the owners manual because it has numerous features and functions to long to list here. 

AT4’s 4WD system consists of Auto, 4H, 4L and 2WD gearing positions, plus it shares the dash with selectable driving modes of Normal, Sport and Off-Road. The latter sensitizes the accelerator pedal for finer control of torque to the wheels on grass, gravel, dirt and snow covered roads. 

HVAC controls are large and easy to use with some functions addressable on the display. Sierra’s console offers a wireless phone charger and an array of auxiliary switches have separate purposes including a trailer brake controller. There’s also a segment first Rear Camera Mirror that has a dual function by bypassing obstructions, passengers or cargo with the ability to tilt and zoom the view. Phew!

Sierra’s heated back seat is similarly comfortable as the fronts for three adults or four youngsters. Behind the outboard portions of the seat are hidden storage bins for small item storage. Flip the split folding seats up against the bulkhead and there’s a full-length storage tray underneath for additional small items. 

Handling wise, as a big truck is has big truck driving dynamics with variable steering assist that helps keep the 2500 centered and easier to park and maneuver. 

Ride quality on 8-lug wheels shod with 20-inch Goodyear tires that have a 9-inch width, is uncannily smooth for a three-quarter ton truck. Load up the cargo bed and it rides even better. 
Sierra AT4 Crew Cab does not come cheap. And options are pricey. The test truck started out with a base price of $57,700 but rose sharply after $18,610 of options. The list includes the Duramax Diesel ($9,890); AT4 package ($4,215); Driver Alert Package II ($645) and included forward collision warning, lane departure warning, auto emergency braking, intellibeam headlights, following distance indicator, safety alert seat (vibrates when a dangerous situation is sensed); Gooseneck/5th wheel package ($545) and Onyx black paint ($195) plus delivery $1,595 took the bottom line to $77,155. If having a business of some kind, perhaps the Sierra can be a tax deduction. 

Sierra AT4 Crew comes with a 3 year, 36K bumper-bumper, 5/100K, powertrain that includes roadside assistance, courtesy transportation and free first maintenance visit warranties. 

The Sierra AT4 is not your typical three-quarter ton pickup, as it possesses the latest technology and features never before offered on a truck. It’s quite an impressive hauler. 
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