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H3 Hummers Built to Explore

Posted in Features on November 15, 2015
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The third line to follow the Hummer legacy consisted of the H3 models produced by General Motors for the ’06-’10 model years. There were two versions: the four-door SUV and the two-door H3T pickup with a 5-foot bed (’09 and ’10 only). They were built primarily on the same chassis used for the Chevy Colorado/GM Canyon pickups with a wheelbase of about 112 inches for the SUV and a substantial 134 inches for the H3T.

The H3 models were originally released with the L52 3.5L I-5 engine but were upgraded a year later to the LLR 3.7L inline-six. Buyers that opted for the Alpha model starting for ’08 would get an LH8 5.3L V-8. All H3 models were equipped with full-time 4WD using either the Borg-Warner 4493 transfer case with 2.64:1 low range gearing or the Borg-Warner 4494 with 4.03:1 low range gearing. Electric locking differentials were optional, with some models offering only a rear locker. The optional front lockers were available for ’09-onward.

While you don't see a lot of Hummer H3s prowling the trails, we know of two that certainly do spend a lot of time off the highway. Mark and Kristina Wells wheel an H3 Alpha Adventure model, and James Gill tackles trails in an H3T truck. Both are ’09 rigs and are equipped from the factory with the Adventure Package. Though these H3 owners live on the southern Florida peninsula, each has ventured up and down the East Coast and nearly to the West Coast seeking fun in the dirt.

Take a look at what these guys have done to turn their H3 Hummers into rigs that can comfortably travel long distances, haul plenty of camping gear, and tackle some quality 4WD trails.

James' H3T has the 3.7L I-5 engine. He's tweaked the power output upward a bit with a PCM tune and addition of an Air Doc intake. Mark's H3 Alpha came equipped from the factory with the 5.3L V-8 engine, and both Hummer engines are backed by a Hydra-Matic 4L60-E four-speed automatic (0.70:1 overdrive). Some H3s, though rare, were sold with an Aisin AR5 five-speed manual transmission (0.73:1 overdrive).

Up front, the H3 models use independent front suspension with torsion bars. Both of these vehicles have been leveled by an increase in torsion bar preload. James also uses an Outfitter Design front differential bushing kit to eliminate excessive movement of the center chunk in the frame. Steering is a power-assisted rack-and-pinion unit. Both H3s have been fortified with the addition of an Outfitter Design steering rack reinforcement kit, and the H3T also has heavy-duty tie rods.

The front differential is the AAM 760. Starting for ’08, some of the upgraded H3s began using a cast-iron front housing instead of the previous aluminum version shown here. Both use a 7.63-inch ring gear and 26-spline axleshafts. However, the cast-iron housing is more reliable, allowing less ring gear flex in the assembly under high loads. The I-5 engine models use 4.56:1 axle gearing, while the V-8 Alpha models came with 4.10 gears. An Eaton electric front locker was available on some H3 models and both of these H3s have one.

Out back, the third-generation Hummers use leaf springs with the AAM 860 axle with 8.6-inch ring gear and Eaton electric locker. Four-wheel antilock disc brakes were standard on all H3 Hummers. They also utilized stability and traction control systems, plus tire pressure monitors. James has added a RubberDuck 4x4 rear differential skidplate, plus custom Hunner shock/leaf-spring skids. For added clearance, Mark chose to go with TOMP low-profile lower shock mounts.

Mark's added intake snorkel has pushed his water fording capabilities far beyond the factory-designed 24-inch limit. To allow for running low tire pressure, Mark upgraded to Hutchinson dual beadlocks designed for Boulder Accessories to match the look of the stock H3 wheels. Rubber consists of LT315/75R16 BFGoodrich KM2 Mud-Terrains.

H3 Hummers all came equipped with full-time 4WD, but Mark has supplemented a DOI winch bumper with a T-Max EW-10,000 winch, should rope extraction be needed. For lighting after the sun sets, there are front and rear LED lightbars and dual Optima YellowTop batteries to ensure plenty of juice on the trail or back at remote camp.

Since Mark uses his H3 extensively on long trips, he's added a Gobi stealth roof rack and ladder to allow him to carry extra cargo when needed. A large PVC tube on the rack also stores a spare front halfshaft and spare tie rods.

Mark has modified the interior cargo space to better accommodate camping and expedition needs. A Dometic CF-50 fridge sits on a cargo shelf with pull-out drawers in the rear. The interior panel on the rear door has also been modified to serve as a flip down table and expose more storage area for small items. A Hi-Lift jack and Power Tank also ride on custom exterior mounts.

The H3T was offered as a standard model, plus Adventure, Luxury, and Alpha models. James purchased his ’09 H3 truck new in 2009. He was looking for a 4WD with good factory options that wouldn't need a lot of aftermarket work. He chose the Adventure Pack model with front and rear lockers driving 33-inch tires, knowing he could swap up to 35s with very little effort.

The first thing you'll spot up front on this H3T is the Thor Parts winch bumper and SMA brush guard. Tucked in there is a Smittybilt XRC Comp 10k winch along with a 20-inch Rigid LED lightbar for running darker trails. These two rigs are not your typical H3 mall runners.

James maintains the factory 16-inch aluminum wheels that have been blacked out. They're wrapped with upsized 35x12.50R16 Cooper Discoverer STT tires. Ridge Demon rock rails protect the rockers, and the rear of the truck supports a Thor bumper with tire carrier. It's quite interesting watching James maneuver the lengthy 134-inch wheelbase through some tight trails.

For security and weather protection on long trips, James relies on a Diamondback hard bedcover. Under there he carries spare parts, fluids, and tools, along with his camping gear. An IndelB TB41 fridge is bolted down in the rear passenger seating area to keep food and beverages cold.

Speaking of noteworthy H3s, Rod Hall used to race a Hummer H3 in the SCORE Stock Mini class and Best In The Desert 3100 classes. The racer was built at the GM Desert Proving Grounds in Mesa, Arizona. A new production H3 was stripped down, 'caged, and fit with a fuel cell. Fox shocks were added while leaving much of the suspension and powertrain stock per class rules.

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