Are you the owner of a car or SUV with four-wheel drive (4WD) or all-wheel drive (AWD)? Vehicles with these two types of drive trains are becoming more readily available from most car manufacturers.
The terms 4WD and AWD are often used interchangeably, but they don’t refer to the same type of power train.
4WD refers to a system where your vehicle runs with two-wheel drive under normal road conditions. If you drive in a difficult situation, such as ice, snow and mud, you can engage the transfer case to activate 4WD. The power is now transmitted to the road by all four wheels, which helps negotiate extreme conditions.
If your vehicle is AWD, it is one of two types: full time AWD or automatic AWD.
Full time AWD vehicles have a differential inside the transfer case which normally gives the same amount of power to all four wheels. When slipping occurs, a coupling device or clutch unites the front and rear drive shafts to keep torque flowing to the axle with traction.
The automatic AWD may or may not have a differential in the transfer case. In normal driving conditions, it only sends power to two wheels, just as any other two-wheel drive car. As long as all four wheels turn at the same speed, the control system is inactive. When it senses a loss of traction in a powered wheel, it connects the inactive drive shaft to the powered drive shaft so all four tires get some traction.
Both 4WD and AWD are valuable features to help drivers safely get to their destinations. Please note that although both will give increased traction on a slippery surface, neither helps with braking and turning. These systems require care and maintenance, so check your owner’s manual to learn what is needed to keep your particular system in prime operating condition.