Four-Wheel Drive

When engaged, four-wheel drive sends power from the engine to all four wheels simultaneously. So, for example, if one pair of wheels is on ice, the other pair will still get you started. Most traditional four-wheel-drive transmissions lack a center differential, which is a big problem. That can lead to dangerous handling on dry roads, when the four-wheel drive is engaged.
 
Four-wheel drive is not to be confused with all-wheel drive.
 

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