The front drive shaft is an extremely important part of the one- or all-wheel-drive system of a vehicle, as it allows power to be transmitted from the transmission to the front wheels. It not only helps in conveying the engine torque to the wheels, which eventually helps in moving of the vehicle but also contribute in overall efficiency(input and output) of the vehicle. The front drive shaft features technologically advanced, high-strength materials that provide improved durability over conventional components--strength is significantly increased and resistance to torsional stress is dramatically heightened. For enhanced passenger protection, an advanced dual-stage driver's air bag and new outboard-mounted side-impact air bags are standard on select models in the 2004 Rainier line-up. It has been mostly used in front-wheel-drive vehicles to improve traction and stability. This is why most front drive shafts are designed with expansion chambers to accommodate this natural phenomenon, as well as retractable bearings for a more frictionless takeoff.