Four-wheel drive , also called 4×4 (“four by four”) or 4WD refers to type of a vehicle, specifically one with its drivetrain capable of providing torque to all wheel ends of a two-axled vehicle simultaneously.
It may be full-time, or on-demand, and is typically linked via a transfer case which provides an additional output drive-shaft, along with additional gear ranges .
4WD generally refers to systems that are intended for off road use. This is a much less clearly defined term than “awd” as many soft roaders like the CR-V and Toyota Highlander are deemed 4WD when in fact their systems are ill suited for any off road use.
Many 4WD systems are part time systems that do not employ a center differential. This is important to know because the center different