When you are buying a new vehicle, particularly a truck or SUV, you will more than likely be confronted with the terms 4WD (four-wheel drive) and AWD (all-wheel drive). These terms deal with the drivetrain and how power is distributed to the wheels on the vehicle.
What does this mean for you and which one best meets your needs? Let's take a look at how the two work and what conditions they are best suited for.
4wd usually can be turned off and on in most vehicles. Some are always operating in 4WD but generally it is an option you can select when you need it.
When 4WD is activated in a vehicle, the transfer case distributes power equally to both the front and rear of the vehicle. At the front and rear of each vehicle there is a differential, this differential further divides the power equally to each wheel in the front and rear, respectively.
So each wheel in a 4WD vehicle receives the same amount of power. This makes 4WD the preferred choice for extreme off-roading. When turning, however, things are not so great. During turning, the inside wheels should be turning a bit more slowly than the outside ones. With 4WD, all wheels are turning at the same speed. This makes handling during turns a bit more challenging. 4WD is usually found in trucks and SUVs.
4WD should not be engaged when driving on smooth surfaces for extended periods of time as this can cause damage to the drivetrain.
AWD options on vehicles are usually on all the time unlike 4WD which can be switched off and on.
In AWD vehicles instead of a transfer case there are three differentials, front, center and rear. The center one distributes power to the front and rear and then the front and rear differentials distribute that power to their respective wheels.
The difference in AWD vs 4WD in this instance is that the power is distributed to each wheel according to need which translates into better handling especially during turns and sloppy or slippery driving conditions.
AWD is not as aggressive as 4WD and doesn't do as well off-road. It is great in winter weather as computer assesses input from sensor in wheels and adjusts traction and speed as necessary making for more responsive handling. AWD can be found in usually SUVs and passenger cars.