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Hummer H2

Originally Published in Trailer Life Magazine

For those who think an SUV should be more than a luxury car with four-wheel drive, General
Motors offers the new Hummer H2 — an SUV that recaptures the go-anywhere, do-anything
spirit and delivers with truly impressive capabilities. A cooperative effort between GM and
AM General (manufacturers of the original military Humvee and its civilian sibling, the
Hummer H1), the Hummer H2 uses truck- and SUV-chassis components for civilized road
manners, but adds some specialized components and technology designed to make it a
world-class off-roader. The result is a vehicle that is second only to the H1 in off-road
prowess, but at less than $50,000, costs half as much. Despite GM’s marketing endeavors,
there still exists the notion that the Hummer H2 is a reskinned Suburban with big tires and
some military-looking bits bolted on. Not true. In fact, it has very little in common with
the Suburban other than the drivetrain and some chassis parts; most of the components used
in the Hummer H2 are model-specific. It’s even built at its own plant — a
630,000-square-foot facility in Mishawaka, Indiana — right next to the AM General Hummer
H1 plant. To quote GM, “The H2 is essentially a GM-designed vehicle developed with live-in
help and guidance from AM General.” GM does not own AM General, but it does own the Hummer
name. It also shoulders the responsibility for design and sourcing of components and tools,
production engineering, marketing and distribution of the Hummer brand, which is now under
the GM umbrella, like Chevrolet and GMC. AM General, meanwhile, contributes its
manufacturing, engineering and assembly expertise. That’s important, because although the
H2 may be a mass-produced vehicle (40,000 H2s will be produced annually, as compared to
only 1,000 H1s), AM General will remain in the mix, making sure that the Hummer reputation
for off-road capability will not be diluted in the H2 or future Hummer products.
Rugged Construction Almost every aspect of the H2 has been engineered for
maximum off-road capability. The frame is a fully welded, ladder-type design which consists
of three pieces: a 2500-series Suburban front section, a new, mid-frame section and a
1500-series five-link rear section giving the H2 an upgraded 8,600-pound gross vehicle
weight rating (gvwr). The chassis has a comparatively long wheel base and short overhangs
for better approach/departure angles than any other GM full-size truck. To put things in
perspective, the H2’s wheelbase is 7 inches longer than a Chevrolet Tahoe’s, while its
overall length is 9 inches shorter. In addition, the chassis was designed from the outset
so that all drivetrain components could be packaged flush with, or above, the frame rails
to protect them against underbody impacts. Further protection is provided by underbody
armor, which protects the engine, transmission, fuel tank and other areas. Powerful
Drivetrain, Sophisticated 4WD System
From a mechanical standpoint, the centerpiece
of the H2 is its integrated drivetrain, four-wheel drive, traction control and anti-lock
braking systems (ABS), which conspire for maximum control off-road. The venerable Vortec
6000 6.0-liter V-8 is the base (and only) engine, and produces 316 hp at 5,200 rpm and 360
lb-ft of torque at 4,000 rpm. This power is routed to the wheels via a 4L65 E-four-speed
automatic (a heavy-duty variant of the 4L60-E transmission used in GM light-duty trucks), a
two-speed, electronically controlled full-time Borg-Warner transfer case and a pair of
heavy-duty axles with a 4.10:1 final-drive ratio. The transfer case has three modes of
operation, which are controlled by dash-mounted buttons: high range open uses a 40/60
front/rear torque split; high range locked ties the front/rear output shafts together for a
full-time 50/50 torque split; and low range locked provides 50/50 torque split and a 2.64:1
gear reduction in the planetary gear set. A neutral position can be summoned by
simultaneously depressing the 4LO Locked and 4HI Open buttons for 10 seconds. This allows
the H2 to be flat-towed behind another vehicle. Anytime low lock is selected, the slower of
two throttle progression curves is automatically activated using the H2’s Electronic
Throttle Control (ETC) throttle-by-wire system. This curve, designed primarily for rock
crawling (where sudden throttle inputs are undesirable), opens the throttle more slowly for
a given amount of throttle-pedal travel, and limits the throttle plate to 75 percent of its
maximum opening. Low lock also gives the driver the option of locking the Eaton electronic
rear differential by depressing the Rear Diff Locked button, but the vehicle must not be
moving when this selection is made. Traction control and ABS are nothing new, but the
ABS/TCS system in the H2 does have some unique features. For example, anytime the transfer
case is in a locked mode, the driver has the option of depressing the TC2 button, which
relaxes the standard traction-control mode somewhat to allow some wheel spin on surfaces
like gravel, sand and mud. And in the normal traction-control mode, as many as three wheels
can be on a slippery surface, and enough torque will still be supplied to the remaining
wheel to propel the vehicle up a 10-percent grade, according to GM. Likewise, the ABS
system has been designed to function equally well on- and off-road. Using separate logic
schemes, the Bosch ABS system can detect uneven or “deformable” surfaces (such as sand and
gravel) in addition to smooth, slick surfaces such as wet or icy pavement to arrive at the
best braking solution. The system includes GM’s standard Dynamic Rear Proportioning (DRP)
feature, which monitors wheel speed and automatically modulates the pressure applied to the
rear brakes to balance front/rear braking loads. Driving Impressions Our
first drive of the Hummer H2 took us from downtown Chicago, Illinois, to the AM General
proving grounds in South Bend, Indiana. The program provided adequate time to drive the H2
solo on Midwestern highways and backroads, and once at the proving grounds, we had plenty
of opportunity to drive the H2 off-road. We also had the chance to test the H2’s towing
capabilities pulling a 27-foot Sunnybrook Lite model 2706 travel trailer. For a vehicle
with serious off-road intentions, square edges and the biggest tires available on a GM
light-duty truck (LT315/70R17 BFGoodrich tires are standard), the H2 rides and performs
well on-road, and its cabin is comfortable and roomy (although total cargo capacity is
somewhat limited at 86.6 cubic feet) with great ergonomics. There is some tire noise
transmitted into the driver’s compartment, as well as some wind whistle, but other than
that, the driving experience is on par with other large premium SUVs. Off-road, the
impression is that the H2 can go anywhere, and based on our experiences in South Bend, it
can. AM General’s proving grounds not only include an obstacle course, but some of the most
tortuous backwoods trails a deviant mind could muster. Extreme grades (some up to 60
degrees), ruts, mud, water crossings — you name it, the H2 not only handled it, but did so
easily. The various four-wheel-drive modes, traction-control systems and locking rear
differential can make even novice off-roaders feel like seasoned veterans. The H2 has a
maximum tow capacity of 7,000 pounds. It handled the 4,948-pound Sunnybrook effortlessly,
and the vehicle’s short rear overhang prevents bouncing and the dreaded “tail wagging the
dog” syndrome. Performance was about par for such a combination; towing, the H2 managed a
23.6-second 0- to-60 run, with a 40-60 mph time of 13.7 seconds. Solo, the H2 managed 0-60
mph in just over 10 seconds. If you like to camp in out-of-the-way places, and you need a
vehicle that can take you there without drama, the Hummer H2 may be just what you’ve been
looking for.

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