XWD, an acronym for Cross-Wheel Drive and also known as Haldex Generation 4, is an

all-wheel drive An all-wheel drive vehicle (AWD vehicle) is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand. Types The most common forms of all-wheel drive are: ;1x1 : All unicycles Reflects one axle with ...

system designed by Haldex in partnership with Saab. The XWD is a permanent all-wheel drive system, that can pre-emptively and continuously change

torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...

distribution before wheel slip occurs. The XWD system is designed to improve take-off performance by having the capability to lock the front and rear axles fully. During highway cruising, it can adjust torque distribution, allocating as little as 4% to the rear wheels, a feature intended to improve fuel efficiency. Additionally, the system is engineered to rapidly transfer torque distribution to the wheel with the most grip, providing immediate traction in various driving conditions. Using the two couplings, the XWD system can send 85% of its available torque to a single rear wheel. An ECU continuously collects various data from the car's onboard systems, and in conjunction with the ESC, ABS, and TCS, calculates the best torque distribution in the driveline. The XWD system debuted on the 2008 limited edition Saab Turbo X, equipped with an electronically controlled

limited-slip differential A limited-slip differential (LSD) is a type of differential gear train that allows its two output shafts to rotate at different speeds but limits the maximum difference between the two shafts. Limited-slip differentials are often known by the ...

(ELSD), and was gradually made available through the rest of the 9-3 line (in sedan and combi body styles). The XWD was the standard

powertrain In a motor vehicle, the powertrain comprises the main components that generate engine power, power and deliver that power to the road surface, water, or air. This includes the internal combustion engine, engine, transmission (mechanics), trans ...

for the Saab 9-5 from 2010 to 2012, underpinning the 2011

Saab 9-4X The Saab 9-4X is a mid-size luxury crossover SUV that was introduced at the 2010 LA Auto Show. It is based on the all-wheel-drive GM Theta Premium platform, which also forms the basis for the Cadillac SRX. Production of the 9-4X began in ...

and was part of the Saab 9-3X, the XUV crossover introduced by Saab in 2009 based on the 9-3 Sport Combi. The XWD system was also later used in the Opel Insignia.

References

{{Reflist X XWD Four-wheel drive layout