AWD dual range refers to an all-wheel-drive system equipped with a specialized transfer case that provides both high and low gearing options, significantly enhancing a vehicle's capability in diverse driving conditions, especially off-road or when towing.
Understanding Dual Range Gearing
At its core, a dual-range system, often found in a vehicle's transfer case, offers the driver the ability to select between two distinct sets of gear ratios. Dual-range transfer cases offer two sets of gearing: high and low range. This provides a substantial advantage beyond typical single-speed AWD systems.
High Range (High Gear Ratio)
- Purpose: This is the standard gearing used for everyday driving on paved roads, highways, and light trails.
- Functionality: It allows the vehicle to operate efficiently at higher speeds, providing normal performance for most driving scenarios.
- Engagement: In an AWD dual range system, the AWD capabilities (distributing power to all four wheels automatically) typically operate in high range.
Low Range (Low Gear Ratio)
- Purpose: Low range engages a much lower gear ratio, which multiplies the engine's torque to the wheels. This is crucial for situations demanding maximum power and control at very low speeds.
- Functionality:
- Increased Torque: Provides significantly more pulling power, making it easier to climb steep inclines or navigate challenging obstacles.
- Enhanced Control: Allows for greater precision and slower speeds, which is vital for technical off-roading like rock crawling or descents.
- Engine Braking: Offers superior engine braking on steep declines, reducing the strain on the vehicle's friction brakes.
- Engagement: Typically, the driver manually selects low range when needed, engaging the enhanced torque multiplication.
How AWD Dual Range Systems Work
An AWD dual range system combines the automatic, continuous, or on-demand traction benefits of all-wheel drive with the robust torque multiplication of a low-range transfer case. While most traditional AWD vehicles are designed primarily for on-road traction and occasional light off-roading, and thus only offer a single (high) range, some more rugged or purpose-built AWD vehicles integrate this dual-range capability.
This combination allows the vehicle to intelligently distribute power to all four wheels for optimal traction on various surfaces, while also providing the driver with the option to engage low-range gearing for demanding situations where extra power and control at low speeds are paramount.
AWD vs. 4WD: A Key Distinction
It's important to understand the fundamental difference between All-Wheel Drive (AWD) and Four-Wheel Drive (4WD), as the concept of "dual range" is more commonly associated with 4WD systems. However, some advanced AWD vehicles blur this line by incorporating a dual-range transfer case.
| Feature | All-Wheel Drive (AWD) | Four-Wheel Drive (4WD) |
|---|---|---|
| Operation | Full-time, automatic, or on-demand power distribution to all wheels. Operates independently. | Driver-selectable modes (e.g., 2WD, 4H, 4L). Often includes a locked center differential. |
| Primary Use | Enhanced on-road traction (wet, snow, gravel), light off-roading. | Serious off-roading, heavy towing, extreme weather, specific challenging terrains. |
| Gearing | Typically single range (high), with some exceptions offering dual range (AWD dual range). | Often includes dual range (high and low) for versatile off-road performance. |
| Complexity/Weight | Generally lighter, less complex, designed for everyday driving. | More robust, heavier, often built with stronger components for extreme conditions. |
| Terrain Focus | Improved grip and stability on varying road surfaces. | Maximizing traction and torque for obstacles and difficult terrain. |
Benefits of AWD Dual Range
Vehicles equipped with AWD dual range offer a unique blend of versatility and capability:
- Enhanced Off-Road Performance: The ability to engage low range allows for superior climbing, descending, and obstacle negotiation in challenging terrain.
- Improved Towing and Hauling: Low range provides the necessary torque multiplication for pulling heavy loads from a standstill or at very low speeds without straining the engine or transmission.
- Precise Control: Slower speeds in low range offer greater precision when navigating technical trails, minimizing the risk of damage.
- Versatility: Combines the automatic traction management of AWD for everyday conditions with the robust capabilities of low range for specialized tasks.
Vehicles Featuring AWD Dual Range
While not as common as single-range AWD systems, some vehicles are known for offering dual-range capabilities alongside their all-wheel-drive systems. These are typically more adventure-oriented SUVs or crossovers designed for more than just paved roads. Examples have historically included certain models from manufacturers like Subaru (e.g., older Forester and Outback models in some markets), some Land Rover models (e.g., Discovery Sport, Freelander in certain configurations), and specific luxury SUVs with optional off-road packages (e.g., past generations of the Porsche Cayenne or VW Touareg).
It's worth noting that with advancements in electronic traction control, torque vectoring, and sophisticated terrain management systems, some modern AWD vehicles can simulate certain benefits of low range without a mechanical dual-range transfer case. However, a true mechanical low range still offers a distinct advantage in the most demanding situations.
