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Hummer Improved with New Traction Control System

6 January 1999

Hummer Improved with New Traction Control System

1999 Hummer (R) 4-door wagon. A new traction control system and anti-lock brakes make the 1999 Hummer easier to drive both on- and off-road. The traction control system is called TorqTrac 4, or TT4. It simplifies Hummer operation by automatically engaging when it senses a wheel slipping. AM General has also added anti-lock brakes for optimum control during braking. (PR NewsFoto) [AS]

SOUTH BEND, Ind., Jan. 6 -- A new traction control system and anti-lock brakes make the 1999 Hummer easier to drive both on and off-road. The traction control system is called TorqTrac 4, or TT4. It simplifies Hummer operation by automatically engaging when it senses a wheel slipping. AM General has also added anti-lock brakes for optimum control during braking.

"Hummer's new traction control takes the guess-work out of the process," says Bill Thompson, AM General director, fleet sales and commercial services. "Most 4 x 4's off-road success is due to a combination of 50 percent machine and 50 percent driver ability. The Hummer's off-road superiority is now attributable 90 percent to the machine and 10 percent to the driver with the new TT4 system."

How TT4 Works

TT4 utilizes an electronic sensor on each of the four wheels to determine when a wheel is spinning. The sensors transmit a signal to the Electronic Control Unit (ECU), which then determines how to regulate the brake pressure. If the wheel speed is greater than the vehicle speed, the ECU applies the brakes to that wheel, engaging the traction control system and transferring the torque to the wheels with traction. If the ECU senses the brake is locked, it engages the ABS. The Meritor-WABCO hydraulic anti-lock braking system is a four channel add-on unit with an electronic wheel speed monitoring and control system used on medium-duty trucks, buses and motor home chassis.

Couple this with Hummer's geared hub assembly, which provides a gear reduction of nearly 2:1 (doubling the torque to the wheel where you need it most), and there is very little terrain that the Hummer can't negotiate.

Other Improvements

The addition of the TorqTrac 4 system is not the only improvement for the 1999 Hummer. There are a number of other refinements including:

* The heated windshield utilizes finer wires to reduce reflections at night. Heating wires also cover a larger area of the windshield.

* The fuel pump mounting is revised to reduce engine noise.

* The instrument panel is modified. The fuel transfer switch, the panel dimmer switch and the intermittent wiper switch are now illuminated.

* The remote keyless entry is upgraded to a three-button unit. It now offers a lock button, an unlock button which can be used to unlock the drivers' door only followed by all doors and a panic button. The horn chirp can be turned on or off.

* The windshield washer reservoir has been expanded to hold two-and-a- half gallons. A low fluid indicator light has also been added.

* There are new fuel level senders, improving accuracy and damping.

* The wiring system has been redesigned and simplified.

* There are more powerpoints. Under the dash there is a 10-place fuse block. Six are for ignition and four are for the battery.

New Colors

The 1999 Hummer features two new colors. They are Mesa Dusk and Night Storm. These colors are added to the current complement of Candy Apple Red, Competition Yellow, Silver Metallic, Black, White and Bright White.

Keys to Hummer's high mobility

"If Hummer was introduced today, it would be the most innovative vehicle on the market. Designed in 1979, it is still remarkably revolutionary," says Thompson. Hummer has power, agility and durability unlike anything else in existence. As a result, the basic secrets to Hummer's high mobility remain unchanged. They include:

* 16-inch ground clearance (double that of most 4 x 4's)

* An optional Central Tire Inflation System that allows the driver to change tire pressure on the move

* Steep angles of approach and departure

* 72-inch track width with an extremely low center of gravity for stability

* Full-time 4-wheel drive

* A 4-wheel, fully independent suspension system

* A torque-doubling geared hub final drive

* An optional Runflat Tire System that allows the vehicle to travel up to 20 miles at 30 mph on flat tires

Although Hummer is known for its ability off-road, it's easy to maneuver on city streets as well. Power steering, 4-wheel inboard/mounted disc brakes, an anti-lock brake system, 4-speed automatic transmission and a unique suspension system allow the Hummer to maneuver like a sports car. The roomy interior cabin, high-back bucket seats and abundant head and legroom all add to the comfort of the driver and passengers.

Sport Utility or Truck

Although the Hummer is often thought of as a sport utility vehicle, it is actually a Class 3 truck and meets or exceeds all Federal Motor Vehicle Safety Standards for trucks in its class. Safety features include a padded dash, an energy-absorbing steering column, a steel roof and steel doors with side impact beams.

The Hummer's imposing exterior hides a powerful General Motors 6.5L, V-8 turbo-diesel engine with 195 horsepower and 430 lb.-ft. of torque, which is now standard on all Hummer models. The main fuel tank holds 25 gallons of fuel. An additional 17-gallon auxiliary fuel tank, standard on all Hummers, allows the vehicle to travel further without a stop for fuel.

An optional Monsoon premium audio system, customized specifically for the Hummer's unique interior, includes six coaxial speakers, pedestal-mounted tweeters, and a separate subwoofer enclosure for outstanding clarity.

Hummer Origins

Originally designed in 1979, the military Humvee was engineered and built by AM General to meet the U.S. Army's requirements for a new kind of vehicle. Versatile, reliable and easy to maintain, the Humvee replaced several vehicles in the Army's fleet, including the M151 jeep.

Built in Mishawaka, Indiana, the civilian version, called Hummer, was first manufactured in 1992. It is now in its eighth year of production, with approximately 90-percent of the Hummer's components manufactured in the U.S.A. Since production on the military vehicle began in 1985, more than 155,000 Hummers and Humvees have been produced for consumers around the world.

A variety of industries including emergency response, mining and utility all utilize the Hummer, in addition to individual consumers.

For More Information

Individuals interested in learning more about Hummer may visit AM General's website at They may also call 800-REAL4WD (800-732-5493) for product information and the location of the nearest dealer.

AM General Corporation, manufacturer of Hummer, is headquartered in South Bend, Indiana. The privately held company has been a leader in designing and manufacturing light and medium duty trucks for military and government use for more than 30 years. Since 1992, the company has sold Hummers commercially to retail and industrial customers through a comprehensive worldwide network of dealers.