ISUZU's TORQUE-ON-DEMAND® (TOD) is unlike any drive system ever offered on an Isuzu vehicle. This patented system is an automatic 4WD system that provides the best aspects of part-time and full-time 4WD systems without their compromises. TORQUE-ON-DEMAND is standard equipment on the VehiCROSS and all 1999 Troopers with automatic transmissions (All S, Performance and Luxury Packages).

How It Functions When You're Driving

When TOD is activated and the transfer case is in the High range position and TOD is turned on, the TOD control unit receives signals sent from the 12 input sensors, including front and rear axle speed sensors, ABS brake switch and the throttle position sensor. Isuzu's proprietary 3-D mapping software uses that input to determine the amount of force that's applied to the clutch pack.

When the clutch is completely disengaged, only the rear wheels are driven; when the clutch is completely engaged, a 50/50 torque split is achieved (50% of the power goes to the front wheels and 50% to the rear wheels). The amount of torque transferred to each axle (torque split) varies continuously as conditions are changing. Torque demands are continously (every 20 milliseconds) monitored and redistributed as needed, providing unmatched efficiency.

If the rear wheels begin to slip, the control unit detects the slippage and determines the optimum level of torque based on the feedback control logic, and then increases the torque to the front wheels.

What Makes It Different

This system even has the ability to "anticipate" certain driving situations. Using the signal from the throttle position sensor, including acceleration and deceleration, it determines the torque distribution that will be needed. That means an Isuzu vehicle equipped with TORQUE-ON-DEMAND can virtually anticipate road conditions, so it's ready before you realize you need it. For example, if a driver is going down a hill and takes his foot off the accelerator, the TOD system automatically increases torque to the front wheels to improve handling and evenly distribute engine braking to all four wheels. All this happens automatically -- without the driver sensing any changes.

Unlike other all-wheel drive systems, there's a special display on the instrument panel that provides the driver with active feedback. This display shows the performance of the system and the varying degrees of torque split to keep the driver informed of varying conditions that might otherwise go unnoticed.

There are three lights on the TORQUE-ON-DEMAND display; they represent:

No bars illuminated: approximately 100% rear-wheel drive;
0% front-wheel drive.

One bar illuminated: approximately 85% rear-wheel drive;
15% front-wheel drive.

Two bars illuminated: approximately 70% rear-wheel drive;
30% front-wheel drive.

Three bars illuminated: approximately 50% rear-wheel drive;
50% front-wheel drive.