Some builds start with a brand-new truck. This one started with a truck we've had since day one.
Our 2005 Chevrolet Silverado LLY Duramax has been part of DmaxStore since it was new and has accumulated just over 70,000 miles. Over the years, it has evolved into something completely different: a straight axle swapped Duramax built to handle 40-inch tires, trail use, and plenty of miles on the road.
From the Dynatrac 60 and custom Kryptonite steering to the 62-Gallon TITAN Fuel Tank and built Allison transmission, nearly every area of this truck has been touched.
Here's the complete breakdown of our 2005 DmaxStore LLY build.
Watch the Full LLY Build Breakdown
Straight Axle Swap & Suspension
The biggest change to our LLY is underneath it.
We ditched the factory independent front suspension in favor of a Dynatrac 60 solid front axle with 4.56 gearing. The conversion uses a WFO four-link setup with frame reinforcement plates and coilover towers paired with ADS coilovers, bringing the truck to 9 inches of lift.
Steering was built around Kryptonite steering components, including the drag link, track bar and tie rod. Because this is a fully custom solid-axle conversion, we fabricated custom high-clearance steering arms and supporting components to integrate the Kryptonite steering with the Dynatrac 60.
With 40-inch tires, steering assist was another necessity. A PSC steering box with hydraulic assist makes the truck significantly easier to maneuver despite the tire size.
Out back, the truck runs Deaver progressive rear leaf springs with factory rear shackles and hangers.
Suspension & Steering
- Dynatrac 60 solid front axle
- WFO four-link conversion
- WFO frame reinforcement plates
- WFO coilover towers
- ADS coilovers
- Kryptonite tie rod
- Kryptonite drag link
- Kryptonite track bar
- Kryptonite sway bar end links
- Custom high-clearance steering arms
- PSC steering box
- PSC hydraulic steering assist
- Custom sway bar
- Deaver progressive rear leaf springs
- WARN locking hubs
40-Inch Nitto Trail Grapplers & Method Wheels
A straight-axle Duramax like this needs a wheel and tire package to match.
The LLY runs 40x15.50 Nitto Trail Grapplers mounted on 20x10 Method NV605 wheels with custom OMF beadlocks. The 40-inch Trail Grapplers give the truck the aggressive footprint and off-road capability the solid-axle setup was built around, while the custom beadlocks complete the purpose-built look.
Wheels & Tires
- 40x15.50 Nitto Trail Grapplers
- 20x10 Method NV605 wheels
- Custom OMF beadlocks
Wilwood Big Brake Upgrade
With 40-inch tires adding significant weight and rotating mass, upgrading the braking system was essential to maintaining stopping power and control.
The LLY received Wilwood TX6R six-piston big brake kits front and rear. Making the front brakes work with the Dynatrac 60 required another custom touch: steel adapters were fabricated to mount the Wilwood hardware to the axle's knuckles.
The result gives us the additional braking performance needed for a heavy Duramax on 40s.
LLY Duramax Engine Upgrades
We didn't want to build this truck around peak horsepower. Instead, the engine modifications focus heavily on addressing airflow restrictions and improving the way the LLY breathes.
On the intake side, we installed an S&B cold air intake and S&B intake elbow to improve airflow into the engine.
We also upgraded the factory intercooler piping with Banks boost tubes. The factory driver's-side boost tube can rub through and create a major boost leak, while the steel Banks tubes eliminate that weak point.
Engine
- S&B cold air intake
- S&B intake elbow
- Banks boost tubes
DmaxStore Stage 5 Allison Transmission
Behind the LLY is a DmaxStore Stage 5 built Allison transmission.
We retained the original five-speed configuration but built the transmission to handle significantly more power than the truck currently produces, leaving plenty of room for whatever direction we decide to take the engine in the future.
The factory transfer case was also replaced with a Ford NP273 transfer case to better integrate the drivetrain with the Dynatrac 60 front axle. ARB air lockers were added as part of the drivetrain setup.
AirDog Fuel System & 62-Gallon TITAN Tank
Range and fuel delivery were both addressed.
An AirDog II-5G is tucked up inside the fender to help protect the system from rocks and debris while off-road.
We paired it with a massive 62-gallon TITAN fuel tank, giving the LLY considerably more range for long drives and trail trips where fuel isn't always conveniently available.
Fuel System
- AirDog II-5G
- 62-gallon TITAN replacement fuel tank
Exterior & Lighting
The exterior was designed around functionality without losing the classic look of the 2003–2007 Silverado.
Up front is a Flog Industries Demon Series Front Bumper finished in fine-texture black with contrasting white fog pockets. We modified the bumper to accept a Smittybilt 17,500-lb winch and custom fairlead for trail recovery. Baja Designs Squadron Pro lights were integrated into the fog pockets with additional Baja Designs LP4s mounted above the bumper.
A Royalty Core grille and AlphaRex LED projector headlights modernize the front of the truck while retaining the unmistakable cateye look. Behind the grille sits a Max-Flow Arctic Series transmission cooler to help control Allison temperatures.
We also designed our own heavy-duty DmaxStore A-pillar light brackets to support large Baja Designs LP6 lights without excessive movement. The brackets are gusseted for additional rigidity while maintaining full hood clearance.
Out back, another Flog bumper houses Rigid diffused lighting. The Recon taillights were disassembled and customized with individual Rigid lights to provide substantially more usable light in reverse.
Exterior
- Flog Industries Demon Series front bumper
- Flog Industries rear bumper
- Smittybilt 17,500-lb winch
- Custom winch fairlead
- Baja Designs Squadron Pro fog lights
- Baja Designs LP4 bumper lights
- Baja Designs LP6 A-pillar lights
- DmaxStore A-pillar light brackets
- Royalty Core grille
- AlphaRex LED projector headlights
- Max-Flow Arctic Series transmission cooler
- Custom Recon/Rigid taillights
- Rigid rear diffused lights
- Painted factory-style tow mirrors
- AMP Research PowerStep XL running boards
- Integrated tailgate backup camera
- Fresh bedliner
- Bed toolbox
Interior & Electronics
Inside, the goal was to modernize the 2005 without taking away from the character of the original truck.
An Edge CTS3 mounted in an Edge dash pod gives us easy access to engine and vehicle parameters without cluttering up the windshield. The gauge cluster was customized by NorCal Gauge Repair with DmaxStore branding, white numbers and red needles.
The factory seats were recovered in Katzkin Tuscany leather with perforated inserts and contrasting white stitching.
We also installed a Fleece tap-shifter conversion, giving the five-speed Allison an LBZ-style manual gear-selection function while retaining the factory Tow/Haul operation.
A Pioneer double-DIN head unit controls the JL Audio system, including dual 12-inch subwoofers. Lighting, compressor and locker controls are integrated into the cab using ARB switches and a Switch-Pros system mounted overhead with a custom 3D-printed bracket.
Interior
- Edge CTS3 monitor
- Edge dash pod
- Custom NorCal Gauge Repair cluster
- Katzkin Tuscany leather seats
- Fleece Performance tap-shifter conversion
- Pioneer double-DIN head unit
- JL Audio speakers
- Dual 12-inch subwoofers
- Switch-Pros lighting controls
- Custom overhead Switch-Pros mount
- ARB compressor and locker controls
A Different Kind of LLY Build
Our 2005 LLY has come a long way from the truck we bought new more than two decades ago.
With only 70,000 miles on the truck, the goal wasn't to completely reinvent the Duramax under the hood. Instead, we focused on building a capable, unique GMT800 around it: solid axle, 40-inch tires, hydraulic-assist steering, serious braking, more fuel capacity and the supporting drivetrain to make it all work together.
And like most shop trucks, it's never truly finished.