With all this ability to crawl along at crazy angles, plus traction from two lockers, you find yourself routinely operating at unusual degrees of tilt. When you come to a rock wall, it's easy to lock up, take the high side, and not worry about the angle. You can actually drag the mirror that way, as we remembered an instant too late.
The new Duramax 6600 makes a huge difference. The 6600 makes 300 hp at 3,000 rpm and 520 lb-ft at 1,500 rpm. The engine produces enough low-end torque to loaf along on the trail all day long with hardly a tap on the accelerator. Torque output is up 16 percent compared with the previous 6.5L turbodiesel. But it's on the highway where a 46 percent increase in horsepower provides vast improvement. For the first time ever, an H1 can whip out from behind a line of trucks on a mountain pass and accelerate. At one point, our speedometer indicated 93 mph, which is about all you want to do on 37-inch dual bead-lock tires. Interior noise, even on the soft-top we operated, is significantly reduced. There is still the sound of MT/R tires, some wind noise at highway speeds, and always the whine of a big turbo, but you can actually hear the radio, and you don't have to shout to the passenger.
Handling the torque is an Allison 1000 five-speed automatic, moving power through a full-time NVG 242 transfer case and on out to 1.92:1-geared hubs, which all adds up to a crawl ratio of better than 41 to 1. After an early morning highway blast, we spent the better part of the day in 4-Lo around Pyramid Lake, in Nevada, on steep canyon tracks, occasionally detouring to address suitable test obstacles. It was the kind of trail work "I guarantee you, no other production vehicle could take on," says Rod, a man not given to dramatic pronouncements.
He could be right. We took on terrain where we actually needed both lockers. We walked up vertical stairsteps so steep there was nothing but sky in the windshield. In those climb situations, the H1 is pretty much point-and-shoot, with the torque, the lockers, and traction control maintaining forward motion, and the gearing working in your favor. We just eased into it, waited for the front end to come down, and steered away. On the downhill sides, 12-inch disc brakes let us ease the 7,000-pound Alpha off steep drop-offs. We aired up and down on the move, using the central inflation system, which could really spoil you. As the day wore on, it all became routine. We smelled the desert sage, saw pronghorn antelope, and checked out the abandoned Nightingale Mine. And we did it with essentially zero stress on the machinery, operating well within the capability of the design envelope.
We always thought an H2 was a pretty good trail machine, but on an H1, you get more. You get dual batteries. You get a canister-type air cleaner that keeps water and dust out of the intake. You get real bead locks on runflat tires. You get a 12,000-pound winch loaded with 5/8-inch cable. You get steering gear that uses a 1-1/2-inch output shaft, like on a dump truck. You get no fewer than five coolers, including the turbo intercooler, the transmission cooler, and the fuel and power steering coolers. The transfer case is cooled via radiator fluid, and even the engine EGR is cooled and reburned to reduce exhaust soot.