Four by Four, is typically used on off-road vehicles - or at least vehicles with all-terrain capabilities.
Power goes from the transmission to what is known as a transfer case. Then the maximum torque is divide among the front and rear axles using the transfer case.
When the transfer case splits power evenly, it ensures that each wheel turns at the same speed.
Best traction in off-road conditions.
On/Off feature for fuel efficiency.
More weight and complex.
Not suitable in all conditions
Two wheel drive (2WD)
The engine’s power is used on two wheels that spin to make the vehicle move.
Front Wheel Drive uses the two front wheels to move. Front-wheel drive designs are cheaper to manufacture and more space-efficient than rear-drive systems. Plus, FWD has the added advantage of better traction while climbing hills because the engine’s weight is in equilibrium over the front wheels.
Rear Wheel Drive uses the two rear wheels to move.
For trucks, RWD allows the use of heavy components, which provides better traction with a hefty load. On a performance car, rear-wheel-drive improves handling by balancing the car’s weight more evenly front to rear. Since the front wheels are deprived of both driving and steering a designer cam concentrate on increasing the handling.