This ’15 GMC Went from Okay to Oh Wow in One Day

Javier Gomez owns a shop in Fontana, California, called Gomez Custom Wheels & Tires—and he’s pretty obsessed with driving cool trucks. Over the years, he’s owned a few nice ones, too, as he is never satisfied with driving them the way they came off the production line.

His latest daily driver is this ’15 GMC Denali 2500HD. Just a few days after he brought it home from the dealership, he had it in the shop bolting parts onto it. As you saw in a previous article in Diesel World, Javier put a nice CST lift on the truck. That took one day. After driving the truck for a few days, Javier got the itch to do more. So he ordered up a bunch of aftermarket parts and spent another day bolting them on. We were lucky enough to be there to photograph the installs and let you see what all was involved. Follow along as we bring this nice Denali into “Oh Wow” territory. DW

1 The crew at Gomez Custom Wheels & Tires started off by lifting the tri-fold tonneau onto the top of the bed rails.
2 The folded-up tonneau was first aligned with the front of the bed. The next step was to get underneath the cover and attach the Lund-supplied clamps, starting at the front.
3 The clamp was a super-slick design that takes only seconds to attach.
4 The tonneau simply folds out in three pieces to cover the entire bed. A quick check to verify that the cover was square on the truck (it was) and then all that was left was to install one more set of clamps.
5 When you want to run the tonneau cover in the open position, there’s a snap that keeps it from flopping around.
6 We headed over to the T-Rex offices to let them install the grille, since it was one of the first off the production line. The first thing they did was to remove the factory grille.
7 Once the grille was off the truck, the factory center section had to be removed.
8 Here the center section is being pulled free from the shell.
9 Javier chose to go with T-Rex’s latest X-Metal grille design that incorporates the company’s own LED light bar.
10 Now it was just a matter of putting the new T-Rex grille into the factory shell. A pilot hole was first drilled and then a screwdriver was used to attach the screws to the grille shell.

11 & 12 With the new grille installed in the factory grille shell, reinstalling the entire assembly is easy enough: Just pop it back in and run the screws in. The blue tape was used during the entire installation to protect the chrome from scratches.
13 With the grille done, and before wiring the grille’s LED bar, we headed back to Gomez Custom Wheel & Tire to keep installing parts. Here’s the 50-inch LED light bar from Rigid Industries: It took two guys to span the light bar across the front of the truck’s cab.
14 There’s a rubber strip that runs along the roofline just above the door. Javier’s crew cut a portion of the rubber out in order to fit the Rigid LED light mounts there. Holes were pre-drilled in the channel where the rubber was cut out. The bracket was then bolted down there.
15 Here’s a good look at how the bracket fits down into the channel.
16 The Rigid Industries 50-inch LED light bar is pretty darn good looking. And it puts out a ton of light.
17 Wiring harnesses for the LED lights are supplied with the grille and roof bar,
18 The power cord for the Rigid lights was run down the window channel and into the engine compartment. The harness from the grille was also run into the the engine bay. A 12V positive, ground and a 12V key on signal are the only electrical connections that needed to be made.
19 The location of the switch is up to personal choice, but a low part of the dash seems like a good spot.
20 Next on the agenda was a set of electrically operated Amp Research power steps. The power hinges are the first things to be installed. Luckily, they use some available holes in the truck, so locating the proper position is easy.
21 The steps use two hinges each: one powered and the other not. Here’s an underneath view of the step’s non-powered idler hinge.
22 These little LED lights turn on when the steps are deployed, making nighttime entry and exit a bit easier.
23 After both hinges are attached to the truck, the running boards are moved into position on the hinges. The Amp Research steps come with a wiring harness that makes the install pretty easy. You no longer have to find a hot wire to splice into–just plug it into the OBDII port and you’re done.
24 A set of American Force wheels were next on the list of mods. The American Force wheels needed be outfitted with the GMC’s factory installed Tire Pressure Monitoring System sensor so no codes will get thrown. It simply bolted into the Schrader valve hole.
25 Javier had the crew mount up a set of 37-inch Toyo Open Country tires on the AF wheels.
26 Balancing the big wheels and tires is an important step in the process. Don’t skip it.
27 Lastly, Javier wanted a cool exhaust tip but didn’t want to change the factory exhaust; he got a tip from RBP and then talked to the Chevy dealer about exactly how much of the factory exhaust he could cut off to make the RBP tip fit. After the trimming, the factory exhaust was given a nice sanding down to take away sharp edges.
28 The RBP tip fit on the factory exhaust perfectly. A few 1- inch welds were then laid down to secure the tip.
29 After a long day of wrenching, Javier’s GMC was ready to hit the road in style.


Lund International

T-Rex Grilles

AMP Research

American Force Wheels

Toyo Tires


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