DmaxStore's 2024 GMC AT4HD Build: A Fusion of Performance and Style

As soon as we laid our eyes on this Thunderstorm Grey AT4 at the dealership we could see the potential, lift kit, tires, wheels, and many more modifications could make this the ultimate daily driver and weekend hauler truck. From the plush AT4 interior with the refreshed interior and finally a modern layout there was no doubt that this would be a perfect project truck for us at DmaxStore. A truck to showcase the best products in the industry all on one beast of a truck.

CST Lift Kit

The factory wheels and tires left something to be desired so we immediately ordered a CST Performance Suspension Lift Kit along with their 2.5 series adjustable compression shocks. The CST lift kit paired with their shocks provides unparalleled ride quality and unbeatable quality. While the price may be a little bit more than your average budget lift kits, you can rest assured that you are getting more for your money. These kits are manufactured in the USA down in Southern California with the most heavy duty crossmembers that are a work of art. When it comes to the installation of the CST 4" lift kit it also blows the rivals out of the water, nobody likes cutting up a brand new truck and CST knows that, out of all of the lift kit manufacturers that we have installed on these trucks the CST lift requires the least amount of cutting. Having to only trim a couple sections of the rear frame ears to allow clearance for the new dropped crossmembers. This kit also keeps a stock appearance by maintaining the stock torsion bar location so it is not hanging under the truck, but rather a nice clean look with clearance to match.

Wheels & Tires

By raising the ride height by 4" we needed to get a set of tires and wheels that would fill out the wheel well properly, and we went with a 20" Black Rhino Sentinal wheel and the Toyo RT Trail tire in a 37" diameter and a 12.5" width to provide a perfect stance for a daily driver or weekend warrior truck. We run Black Rhino wheels on many of our trucks and have always been pleased with the quality of the wheels, and here we went with a 20x9.5 +12mm offset wheel to keep the tires from sticking out too far. The Toyo RT Trail is a hot new tire and it is one of our favorites as the wet, snow, and icy traction has been outstanding thus far and they tow incredibly well, one of the best HD truck tires on the market at the moment.

Kryptonite Steering & Suspension

After adding a set of heavier wheels and tires that will add some undue stress on the steering and suspension components and we decided to go with the tried and true Kryptonite Products Ultimate Front End Steering Package, Upper Control Arms, and Lower Ball Joints. The front end package comes with everything that connects the steering box to the knuckles, it is vital to upgrade these components as the factory parts just aren't up to par when you are outfitting your Duramax with larger wheels and tires or adding more power. This kit includes the Kryptonite tie rods, idler arm, idler support, frame gusset, pitman arm and SS centerlink. One of the best features of this kit is that it has the strength of a "straight centerlink" but without the reduction in steering radius so it is easily used as a daily driver after installing. The idler and pitman arms are also much much larger that the oem components with improved joint designs that will last a lifetime, and yes Kryptonite does cover all of their parts with a lifetime warranty. The Kryptonite upper control arms are a great upgrade to have some additional adjustability when it comes to droop travel as well as alignment specs, the factory arm prematurely hits the frame perch right underneath the arm and that will cause premature ball joint failure, we have even seen the arms crack in half! Even though this truck only has 5,000 miles at the time of installation we wanted to replace the ball joints as we had them wear out in about 20,000 miles on our 2022 Chevy Silverado 3500HD and all we had to do was press out the factory joints and press inthe improved Kryptonite joints since the knuckles were already being taken off with the installation of the lift kit. 

Front Bumper & Grille

The AT4 trim truck already has a pretty good looking front fascia, from the cool headlights, body color bumper, and black grille with brushed accents it will most definitely turn the heads of truck owners. We felt that it could be improved in favor of a more aggressive and offroad oriented look like the AT4 badge on the doors suggest. We went with one of our favorite grille manufacturers for these trucks, Royalty Core, we have ran their grilles on many of our previous trucks and they are top notch. We opted for the dual light bar option across the front to have a set of Baja Designs Onx6 light bars to light up the rural roads when the sun dips below the mountains. For the bumper we opted to customize it to our liking to have the best fit and finish on the market while having the ability to hold a Warn EVO 12 winch to pull the Fords out of the ditches. This bumper gives the truck an aggressive look without making the truck look like it has a fat lip like many of the new bumpers do. We also opted for a set of the Baja designs Squadron SAE fog lights, one set in amber and one in white, these are a very welcome upgrade over the disappointing factory fog lamps.

SSBC 8 Piston Brake Calipers

When it comes to stopping loads over 22,000 lbs it is vital to have a brake set up that is up for the task, and those 2 piston calipers that come on the truck from the factory just aren't it. We opted to upgrade to the SSBC direct bolt on front and rear barbarian 8 piston callipers that will stop any truck in its tracks. It is a night and day improvement over the OEM calipers. To make sure the new calipers don't overheat and warp the rotors we went with the zinc plated Powerstop drilled and slotted rotors. This is a deadly combo for the brakes as it not only looks a heck of a lot better but stops on a dime!

Rear Suspension

We know that this truck will be seeing some heavy trailers, from out 40 foot gooseneck that gets loaded down to max capacity or taking out our Polaris RZR Pro R to the trails in our Momentum Toyhauler. This truck needs to be prepped to be fully loaded but still need to ride good on the drive to work. We saw what ReadyAir was doing with their Load Leveling Helper Spring Kit that features 2 OE style air bags on each side and attaches to the outside of the frame and the top of the leaf spring. The OE style air bags DON'T compromise the ride quality when they are unloaded and will also support 7,200 lbs so we can level our gooseneck, the toyhauler, and even a load of gravel if we need to. To match the front 4" kit we went with a 2" rear block that makes it sit perfectly level when the front is adjusted to 4". This is a great option for those of you who actually use your truck to haul trailers without being too tall and rendering your truck useless or needing some crazy drop hitch that needs support bars and all sorts of modifications just to tow a trailer. This will let the truck float down the road like a 1500 but it will also be able to tow at max capacity when loaded down. 

Banks Ram Air Rear Differential Cover

Since we knew we were going to push this truck hard when towing it is important to keep that rear differential happy,and the best way to do that is with proper fluid, and keeping that fluid cool and flowing well. The Banks Power Ram Air Rear Differential Cover does just that, by scooping the air from under the truck through the high quality die cast aluminum finned cover that dissipates heat better than EVERY other cover on the market, it also features improved fluid dynamics and properly lubricates the axles, pinion and ring gear to give the longest life possible to the differential. We paired this with some AMSOIL Severe Gear 75w-140 to have some thicker oil to maintain better lubrication between the contact services when the differential does warm up when pulling those long grades.