Powertrain

Standard in the H3T is the Vortec 3.7L I-5 with dual overhead cams and variable valve timing. This inline five-cylinder engine offers an excellent combination of power and efficiency, delivering 242 horsepower (180 kW) at 5600 rpm* and 242 lb.-ft. of torque (328 Nm) at 4600 rpm. It is backed by a five-speed manual transmission or an available four-speed, electronically controlled automatic.

The H3T Alpha’s 5.3L engine is a powerful and efficient member of GM’s legendary small-block V-8 family. It is rated at 300 horsepower (224 kW)* and 320 lb.-ft. of torque (434 Nm).* An aluminum cylinder block is used with the H3 Alpha’s engine. It helps reduce overall mass and maintains a more desirable front-to-rear weight balance.

A Hydra-Matic 4L60 electronically controlled four-speed automatic transmission is paired with the 5.3L engine. Flat towing is enabled on all H3 and H3T models.

Chassis

The H3T’s frame and suspension system are based on a stretched version of the H3 SUV’s chassis and suspension – the same race-proven design found on Baja 1000-winning stock-class race trucks. The wheelbase measures 134.2 inches (3,409 mm) – 22 inches (86 mm) longer than the H3 SUV.

A ladder-type frame is the truck’s foundation and it has a modular, three-piece design that incorporates fully boxed components for outstanding strength and stiffness. An independent SLA torsion bar front suspension and multileaf Hotchkiss-type rear suspension are used. There are two suspension packages available:

• Z85 Heavy-Duty Handling and Trailering – This standard suspension delivers an excellent balance of on-highway comfort and off-road capability. It includes 32-inch all-terrain tires mounted on 16-inch, smoke-color steel wheels, specially tuned heavy-duty shocks and either a 4.56-ratio (3.7L) or 4.10-ratio (5.3L) rear axle.
• Off-Road Adventure – Designed for more aggressive off-road performance, this optional suspension package includes taller, 33-inch tires, specifically tuned shocks, locking front and rear differentials, 4.03:1 low-range gearing in the transfer case and industry-leading crawl ratios of either 68.9 with the manual transmission or 56.2 with the automatic.
  To support the torque output of the 5.3L V-8, the H3T Alpha’s front differential case is made of cast iron; other models feature an aluminum case. V-8-powered vehicles also receive higher torsion bar rates to support the increased mass and specific shock valving. The chassis and suspensions were validated in real-world testing on off-road trails in Moab, Utah; the Rubicon Trail in California, and other challenging off-road venues.