The key difference between AWD and 4WD is the drivetrain that provides power to wheels of a vehicle by different methods. AWD is drivetrain that have a front, rear, and center differential to provide power to all four wheels of a vehicle. 4WD employs two differentials and a transfer case to provide power to all four wheels of a vehicle.
All-Wheel Drive (AWD) is a type of vehicle or powertrain that is capable of providing power to all four wheels of vehicle, whether full-time or on-demand. The most common forms of AWD are: 4×4; 6×6; and 8×8. In 4×4, there are two axels with both wheels on each capable of being powered. While in 6×6, there are three axles and in 8×8 there are four axles with both wheels on each capable of being powered. AWD vehicles may be either part-time all-wheel drive, or full-time. On-demand also known as part-time where one axle is permanently connected to the drive and other is being connected as needed. Full-time also known as permanent as in this axles are permanently connected, with or without a differential.
Four-wheel drive is form of all-wheel drive powertrain capable of providing power to all four-wheels of vehicle simultaneously. It may be full-time or on-demand, and may be connected to multiple drive axles for Hi and Lo ranges. 4WD generally refers to four-by-four vehicles that is general class of vehicles. 4WD refers to vehicles that employs two differentials and a transfer case to provide power to all four wheels of vehicles, meaning that the front and rear drive shafts will be locked together when engaged. This provides maximum torque transfer to the axle with the most traction, but in high traction turning situations. They are also either full-time or part-time 4WD selectable. 4WD is not intended for high speeds without a limited slip mechanism.
- 4WD shows best traction in off-road conditions while AWD provides grip and control in every road conditions.
- 4WD can be turned off to improve fuel economy while AWD just reduces fuel economy and have poor fuel economy.
- AWD safety ratings are higher than 4WD.
- AWD is recommended to be used for on-the-road drive while 4WD is recommended to be used for off-road-drives.
- 4WD is much heavier and consumes extra space as compare to AWD.
- 4WD has both gearing option; high and low while AWD has only the high option.