Allison 1000 Transmission
Fuel economy is also aided by the five-speed Allison transmission often found in the Chevy/GMC 2500 and 3500 pickups. It has more gear ratios than the previous 4L80E transmission it replaced, and it has a higher (0.70:1 vs 0.75:1) overdrive gear for better fuel economy at highway speeds. The Allison is also stronger and rated to handle 620 lb-ft of torque (the previous transmission was rated at 440 lb-ft). New axle halfshafts and steering gear were also added to help deal with the extra torque produced by the Duramax.
Fuel Economy: How Far on How Much
From Los Angeles we headed due north toward Redwood country, where the tallest trees in the world grow. What better place to take the largest (red) SUV on the planet? Driving North on I-5 where the speed limit is 70 mph, the H1 Alpha motors down the highway with little concern for grades, passing slower vehicles, or slugging down the #2 Diesel. We passed a few 6.5 and even gas-powered Hummers on our trip, and it was clear the Duramax brings this vehicle to a whole new level of performance. The direct-injection engine seems to run much cooler than the IDI 6.5L, and we never got the Allison 1000 to break a sweat.
Over our 1,700-mile roundtrip (loaded down with food and camping gear for two) we managed just over 10.1 mpg. Considering the A/C was always on, the speeds we were traveling, and the fact that we dialed the central tire inflation system down a few psi for a smoother ride-it could have been a lot worse. Don't kid yourself here. A machine like the Hummer is built for many things-fuel consumption is the price you pay for its high mobility.
| DURAMAX vs. OPTIMIZER |
| | Duramax (LLY) | Optimizer |
| Displacement | 6.6L/403ci | 6.5L/397ci |
| Block material | cast iron | cast iron |
| Cylinder head material | cast aluminum | cast iron |
| Valvetrain | overhead valves | overhead valves |
| Fuel delivery | direct injectionwith high pressurecommon rail | indirect injection |
| Compression ratio | 17.5:1 | 20.2:1 |
| Horsepower | 300 @ 3,000 rpm | 205 @ 3,200 rpm |
| Torque | 520 @ 1,500 rpm | 440 @ 1,800 rpm |
| Maximum engine speed | 3,250 rpm | 3,400 rpm |
| Fuel Capacity (main + aux) | 29.5 + 22= 51.5 gallons | 25 + 17= 42 gallons |
| Towing capacity | 9,303 lb | 7,867 lb |
Alpha Bits New for 2006
* Duramax 6.6L (LLY) turbodiesel engine
* Allison 1000 (M74) five-speed transmission
* Towing capacity increased by 1,400-plus pounds
* New helical-cut geared wheel hubs
* 3 seconds faster 0-60 mph
* 170 miles increased range
* Stronger axle halfshafts
* 1.5-inch larger brakes
* 2-inch body lift
 This is the original geared...  This is the original geared hub design that multiplies torque inside each wheel of the Hummer H1. The Mercedes-Benz Unimog is one of the only other vehicles to offer this crawling-friendly feature. The H1 Alpha has helical-cut gears (the older, straight-cut version is shown) which are quieter and reduce rocking motions during deceleration and stopping maneuvers. The big disc inside of the tire is part of the runflat tire system. |  The new two-piece 17-inch...  The new two-piece 17-inch wheels have dual bead locks, runflat tires, and work with the central tire inflation system that allows drivers to use an onboard compressor to adjust the pressure in the tires from inside the cabin. |  Our Hummer H1 Alpha came fully...  Our Hummer H1 Alpha came fully loaded with the only two option packages available. The Off-Road Tire Package came with 37x12.5R17 load range "E" Goodyear Wrangler MT/R tires with DuraWall puncture resistance technology for just $100. The Adventure Package cost $5,726 and added a 12,000-pound Warn winch in the front bumper, Eaton electronic locking front and rear differentials, and the new 17-inch Hutchinson wheels. |
 Although the space for passengers...  Although the space for passengers is not what many would expect in a vehicle this large, there is plenty of room for camping gear. You can also get the H1 Alpha with a Wagon body style that encloses this rear section of the truck and includes a fixed roof over the cabin. |  Racing legend Rod Hall began...  Racing legend Rod Hall began running the Hummer H1 in 1993, right after they became available to the public. In that first year of racing the heavy Hummer, the Hall team crossed the finish line of the Baja 1000 in first and second places. His son, Chad, also races Hummers in the Best in the Desert and SCORE competitions. The Hall family's Team Hummer is now racing a Hummer H1 Alpha along with the smaller truck-based H2 and H3 models. In 12 years of racing, the team has racked up 10 class wins in the Baja 1000, 41 Best in the Desert podium finishes, and is the only American team to finish the Dakar Rally in the stock class. |  |
The Farm That Wasn't: Radar Station B-71 "Trinidad"
While roaming Northern California in the H1 Alpha, we noticed something on the map that looked like a piece of armed forces history. Since the Hummer was based on a military vehicle, we thought it was only right to have it visit some relatives during its final voyage. It turns out the dot on the map on the coast of Klamath, California, was a top-secret, diesel-powered, early-warning radar station that was built to look like a farm to avoid detection.
After the Japanese bombed Pearl Harbor, the nation went on alert for assaults on the West Coast. In 1942, enemy submarines shelled a refinery in Santa Barbara, California, and ports in Washington and Canada. A Japanese sub even launched incendiary bombs into the forests of Oregon during September of 1942. To help prevent other incidents, an Army contractor was hired to create radar station buildings disguised as a farmhouse, barn, and an outhouse. They featured two-foot thick cinderblock walls with wood shingles and facades for camouflage. The farmhouse hid a diesel generator (we guess it was a Detroit Diesel, but would like to hear from anyone out there who knows for sure), which powered the SCR-271 radar equipment. In addition to the electronics were two 50-caliber anti-aircraft guns.
Radar Station B-71 (also known as Trinidad or the Klamath River station) was manned by 35 soldiers from the Army Air Corps. They were all armed with rifles and kept the station in operation 24 hours a day, reporting any potential attacks to officials in San Francisco. Near the end of World War II, the Klamath River station was converted to an air-sea emergency rescue station. After the end of he war, Station B-71 was abandoned and became private property until the National Park Service acquired it during the creation of the Redwood National Park.