When shopping around for a new or used vehicle, you will undoubtedly come across different drivetrain options, such two-wheel drive (2WD) and four-wheel drive (4WD).
The powertrain is everything that makes a vehicle move, including the engine and the drivetrain, while the drivetrain is everything that makes the wheels move minus the engine.
There are three common types of drivetrain arrangements: rear-wheel drivetrains, front-wheel drivetrains, and four-wheel/all-wheel drivetrains.
Four-Wheel Drivetrains (also known as Four by Four or 4×4)
Although 4WD and AWD are different, they both transfer power to your front and back wheels, which can be beneficial during muddy, snowy, rocky, and other difficult driving conditions.
You typically see 4WD systems on larger vehicles that are designed with all-terrain abilities, such as trucks, SUVS, and off-road vehicles.
The main difference between 4WD and AWD is that four-wheel drive vehicles use two differentials and a transfer case while all-wheel drive vehicles employ a front, rear, and centre differential.
Four-Wheel Drive (4WD)
When 4WD is engaged, the engine sends power to the transmission, which is then split into the front and wheel axles. The torque gets transferred to the wheels, but the wheels must have traction on the road in order for the vehicle to move anywhere. Otherwise the tires will merely spin as you have probably experienced when stuck in mud or sand.
Let’s say that you get your rear wheels stuck in mud. If you have two-wheel drive (2WD), then your wheels will probably spin and spin. In this case, it might be extremely useful to have four-wheel drive so that your front wheels could get some traction on the road. If power was transferred to the front wheels, where the traction is, you’ be able to successfully get your car out of a sticky situation.
This is essentially what four-wheel drive does. It gives you traction where and when you need it. Although 4WD is a bit more complicated than that, it’s essentially a way to increase traction and power on the road.
It’s important to know exactly how your 4WD system works. For older vehicles, you may have come to a complete stop first and put your vehicle in neutral or park before engaging 4WD.
Newer vehicles, however, can normally activate 4WD with a simple push of a button. Some modern 4WD systems turn on automatically whenever it detects one or more of the wheels slipping.
When to Use 4WD?
Use 4WD in the following situations:
- When you need additional torque/power, such as pulling heavy loads at slow speeds.
- When you descending at slow speeds while hauling a heavy load.
- When you are going over steep inclines and declines, such as rocky situations.
- When you are stuck in snow, mud, or sand; however, stop immediately if your wheels are spinning and follow the advice in this article.
Four-Wheel Drive Advantages
The main benefits of 4WD are traction and power.
If you are climbing a steep hill or are off-roading, you will want increased power in order to get over obstacles and climb steep hills. If you are off-roading you will probably want the extra power that comes with 4WD.
4WD improves traction in dangerous driving conditions, such as snow, ice, rocks, and other scenarios that can make control difficult. By engaging both sets of wheels, traction and control improves.
Additional weight contributes to better grip on the road.
4WD is great for those who like off-roading.
If you frequently drive in conditions where there is low traction, or if you enjoy off-roading, you will greatly benefit from four-wheel drive.
Four-Wheel Drive Disadvantages
In most cases, 4WD is not necessary. It uses more fuel and can also lead to overconfidence, leading to more situations where you can get stuck. Save money and fuel by only using 4WD when you need it.
The main disadvantage of 4WD is added cost for purchase, maintenance, and fuel. The extra equipment (differentials, transfer case, etc.) adds complexity and weight to the vehicle, increasing initial market value, tire wear, and the cost of repairs and maintenance.
The added power and weight of 4WD and AWD systems require more fuel, making them less efficient than their 2WD counterparts.
Added weight improves traction and control, but it also increases the braking distance required to make a complete stop. Lighter vehicles can avoid collision easier than heavier vehicles.
4WD and AWD can cause overconfidence in drivers, ironically leading to more situations where you can become stuck.
Although 4WD improves traction, slow down and use extreme caution on icy, snowy, and slick roads. Overconfidence can lead to dangerous accidents.
4WD Tips and Tricks
4WD vehicles work best when they are regularly used and maintained according to manufacturer recommendations. If you don’t use the 4WD system for extended periods of time, the seals can dry out. It’s best to keep the system lubricated by activating it at least once every few months.
Only use 4WD when you need it to save as much gas and money as possible. Driving 4WD on mild, dry conditions can do damage to your front axles, differential gears, and other parts. Do not use 4WD on dry pavement.
If you get stuck, switch to 4WD and slowly depress the gas pedal to get yourself out. If the wheels start spinning, stop before you dig yourself a deeper hole.