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Durable Duramax: A Chevy 2500HD and Off-Road Trailer Built for Adventure

Posted in Features on January 18, 2018
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Brent Rederick and Amber West of Chandler, Arizona, spend a lot of time in the dirt. That is to say, you'll often find them exploring the Southwest backcountry in some manner of 4WD vehicle. They’ve built a handful of highly modified trail rigs and had used this ’04 Chevy Silverado 2500HD as a tow vehicle for a number of years.

But needs and goals change. They decided the tow rig would take on duty as an expedition-style four-wheeler, and so they donned their work gloves and dug into some serious modifications. What you see here isn’t a diesel with shorty-sidewall tires rolling coal on neighborhood streets. This is a purpose-built recreation rig intended to take this couple exploring over thousands of miles of trails per year, and it has the dirt and scratches on it as proof. We managed to catch them loading down and heading out for another weekend of fun so we could show you their rig in use.

The LLY Duramax diesel has been left stock, save for improved breathing via a MagnaFlow 4-inch after-cat exhaust system. This 2500HD has a ZF six-speed, manual transmission, and power transfer has been improved with a South Bend Clutch dual-disc setup. The transfer case is the stock NP261XHD that’s been upgraded with a Merchant Automotive Transfer Case Pump Upgrade Kit.

Plenty of these trucks sit with a taller stance like this Silverado and run 35-inch tires—but take a peek under this one, and you’ll find an uncommon distinction. It has undergone a healthy solid-axle swap. The owners started with a Dana 60 front axle from a Ford Super Duty and rebuilt it before installation. The factory 4.10:1 gearing was retained, as were the factory disc brakes, except for upgrades to braided stainless lines and fresh EBC Green Stuff pads. After prematurely wearing out the stock Ford unit bearings, the front axle is now equipped with a Dynatrac Free-Spin hub conversion kit. PSC steering components help turn the larger tires on the new axle.

For suspension, a WFO Concepts SAS kit was used along with 2.5-inch, 8-inch-travel King coilovers on new shock towers and 2-inch-travel King air bumps to cushion the last few inches of uptravel. Out back, the factory 11.5-inch AAM axle received 4.10:1 gearing to match the front and an ARB Air Locker. Lift comes from Deaver leaf springs combined with 2-inch drop shackles to provide about 2.5 inches of lift. Damping and limit chores are handled by King 2.5-inch, 10-inch-travel shocks and 2-inch-travel air bumps. The new suspension allows the use of 35x12.50R17LT Nitto Trail Grapplers onto 17x8 Raceline alloy wheels.

The Dana 60 front axle was procured from a ’10 Ford F-250 Super Duty and is filled with 4.10:1 gears. The truck now uses a PSC steering box and a new double-shear pitman arm to tie the draglink to the passenger-side knuckle. PSC heavy-duty ram-assist also resides on the front axle.

Much of the exterior body and paint remain stock, as this is a bona fide trail truck. Hammerhead front and rear bumpers were added, as was a small array of Rigid LED lighting. The front bumper also houses a Warn VR12-S winch with synthetic line.

When headed to the backcountry, the couple now tows their home-built camp trailer behind the Silverado, and it’s capable of following them wherever they choose to explore. It has electrical and air connections to the truck, plus it includes storage for water, extra diesel, propane, food, camp gear, and a CVT Mt. Rainier tent perched on top. The capable trailer also frees up bed space in the truck to allow for hauling firewood and other camp items for a week or more at a time. The vehicle combination works well together and takes them a lot of places in comfort.

The couple installed a WFO Concepts SAS kit in place of the factory IFS setup. The lower links are built from beefy 2-inch, 0.250-inch-wall DOM tubing and the upper links from 1.75-inch, 0.250-inch-wall DOM tubing.
Frontend damping is controlled using 2.5-inch, 8-inch-travel King coilovers with remote reservoirs that are specifically valved for this application. A pair of King air bumps stop upward travel before metal parts contact.
The 11.5-inch AAM rear axle was regeared with 4.10:1 gears that now spin on an ARB Air Locker. A pair of 4-inch-lift Deaver spring packs were combined with longer drop shackles to provide flex and a supple ride for the tail end of the truck. Here again, King shocks and air bumps control the axle movement as it cycles.
The Duramax engine remains unmodified but has been supplemented with dual AGM batteries and a 250-amp Singer alternator to keep the truck batteries and camp batteries well charged. Onboard air is supplied by a Kilby compressor kit and storage tank tucked under the bed.
A beefy Hammerhead bumper is bolted to the front of the Chevy and is populated with a quartet of Rigid LED driving and floodlights. Inside sits a Warn VR12-S winch spooled with synthetic rope should the need for self-recovery or rescue arise.
At the rear of the truck, you'll find another Hammerhead bumper and a Wilco Offroad Tiregate supporting a fullsize spare tire that will fit the truck or trailer.
The truck now articulates better and is much more capable on the trail.
The couple also built a camp trailer to support their exploring addiction. They started from the ground up with a set of 35X12.50R15LT General Grabber tires mounted on steel wheels.
Up top is a CVT Mt. Rainier tent that is accessed from a ladder after the trailer roof is elevated using four servo-controlled linear actuators. Raising the tent platform exposes the contents of the trailer. A Rhino-Rack Sunseeker awning attached to the trailer provides shade when needed.
Once the trailer is opened up, it reveals a Cook Partner two-burner stove, 30-gallon water tank with faucet, 84-quart Whynter refrigerator, 20-pound propane tank, and plenty of sealed storage below the top lid.
Brent built a custom three-axis hitch designed to allow the trailer to easily follow the truck as it traverses rough terrain.
Pop a panel on the side of the trailer and it reveals the nerve center of the electrical system. Electrical power is supplied by two deep-cycle Optima batteries and charged via 4-gauge power cables fed from a 500-amp solenoid and the 250-amp Singer alternator on the Silverado. A 1,000-watt pure-sine-wave Go Power! inverter provides A/C power.
The trailer suspension consists of a double-triangulated four-link setup sitting on adjustable airbags with Rancho RS9000 shocks to minimize bouncing. Brent built the 7,000-pound-rated solid axle that utilizes eight-lug hubs and electric brakes.

At a Glance

Vehicle: ’04 Chevy Silverado 2500HD
Owners: Brent Rederick and Amber West
Stomping grounds: All over Arizona
Build time: One year

Engine: 6.6L V-8 Duramax turbodiesel
Transmission: ZF S6-650 6-spd manual
Transfer case: NP261XHD
Low range ratio: 2.72:1
Crawl ratio: 64.6:1
Front axle/differential: Dana 60, disc brakes, 4.10:1 gears/open
Rear axle/differential: 11.5-in AAM, disc brakes, 4.10:1 gears/ARB Air Locker

Front: WFO Concepts SAS kit, radius-arm link suspension, King 2.5-in coilovers, King bumpstops
Rear: Deaver 4-in-lift leaf packs, 2-in drop shackles, King 2.5-in shocks, King bumpstops
Steering: PSC steering box with hydraulic ram-assist, WFO pitman arm and steering rods

Tires: 35x12.50R17LT Nitto Trail Grappler
Wheels: 17x8 Raceline alloy

Hammerhead front and rear bumpers, Warn VR12-S winch, TracRac sliding truck rack, ARB Elements fridge freezer in bed, dual AGM batteries, 250-amp Singer alternator, custom-built off-road trailer

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