Modern four wheel drive, better known as 4WD, vehicles are quite commonplace today, being sold in a variety of choices from compact SUVs to luxury models. The idea of good traction and motorized drive on all four wheels has long abandoned the perception of being restricted to back country use or military operations. Instead, such vehicles are finding themselves at home in professional as well as family car settings, creating a sense of automotive power blended with refinement and quality.
A bit of explanation tends to be required. A four-wheeled drive or “4WD” or 4×4 transmission involves a vehicle system that can transmit propulsion energy from the engine to all four wheels at once. Most cars and consumer vehicles operate with what is known as a two-wheeled drive or 2WD, where the propulsion only occurs in the front two or rear two wheels.
Newer cars will also be marketed with all-wheel drive, or AWD. Where the AWD system is automatic, it only provides wheel stability. Many lower-end, compact SUVs are sold with this feature. A true AWD vehicle follows the four wheel drive concept, but allows the wheels to spin different via a hybrid differential. It performs like an upgraded 4WD transmission without driveline lockup or wheel skipping which occurs with two wheels on the same axle going at the same speed.
When using the controls in a true 4WD vehicle, the driver has the option to switch to two wheels, 4WD hi, and some older models provide 4WD lo as well. The choice provides a driver the convenience to switch the system to the mode that is most appropriate for the current conditions. Clearly, driving down a dry, regular street or road requires no need for 4WD. Doing so would overwork the engine and consume fuel needlessly. On the other hand, 2WD could be almost useless off-road in a muddy field. Being able to switch back and forth allows the driver to compensate for the conditions as necessary.
Some 4WD vehicles will operate permanently in the 4WD mode. Such vehicles are commonly used for carrying heavy loads or they are used in conditions that require better traction constantly. Larger pickup trucks for construction site use and commercial vehicles are typically chosen with this mode. Some higher-end sport utility vehicles designed for off-road or safari use also come designed with a permanent 4WD transmission as well.
Vehicle control in hostile conditions and less-than-stellar road environments is a key benefit from a 4WD car or truck. Being able to drive when the road is covered with snow or ice, or being able to travel where normal cars would just get stuck make the 4WD transmission a must-have for those who regularly work, live or play in such conditions. Further, those vehicles coupled with a manual transmission get the best response out of a 4WD design since the manual shift changes can take advantage of the gearing faster than an automatic system ever wood. In fact, most 4WD vehicles come in a manual transmission form, although an automatic option is available in some brands.
Vehicles with a 4×4 transmission provide strong automotive power. That said, these vehicles are little low at fuel efficiency Anybody pinching coins when filling up at the petrol station shouldn’t really be using a 4WD vehicle. Further, the added transmission design makes 4WD more expensive when it comes to repairs versus the same needs in a 2WD vehicle.