If your vehicle has all-wheel drive, your engine's driving power is sent to all four wheels for extra traction when needed.
This is like four-wheel drive, but there is no separate lever or switch to engage or disengage the front axle. It is fully automatic, and adjusts itself as needed for road conditions.
You may experience a brief vehicle vibration upon acceleration when driving in slippery conditions. This is normal and is an indication that the all-wheel drive system is functioning properly.