Can You Switch To 4WD While Driving?

When you’re driving through rough roads or unforeseen snowstorms, you might be tempted to switch over to your four wheel drive for better control. However, you might also wonder if that’s even safe to do while you’re driving.

Older 4WD systems generally require the vehicle to be put in park or neutral in order to switch from High to Low. Newer model vehicles have automatic 4WD systems that are button operated. Regardless of the system, it is less stressful on the vehicle gears to make the switch when parked.

4WD is really great to have when driving in bad weather or if you’re looking to venture off paved roads as it creates better traction and driving power. If you find yourself in these conditions, it is important to know when to make the switch. Keep reading to find out when to switch to 4WD and why!

When to Use 4WD

First off, what is 4WD? 4WD, otherwise known as four wheel drive, is when all four wheels receive power. Some vehicles such as Subarus, are 4WD vehicles. This means they are always operating in 4WD; meanwhile, vehicles that are front wheel drive (FWD) or rear wheel drive (RWD) are not. These vehicles only receive acceleration to either the front or rear tires. 

While this leads to easier maneuvering, it results in a loss of traction and control in conditions such as snow, mud, or sand.

Many two-wheel drive vehicles such as SUVs and trucks also have 4WD capabilities. But in order to activate them, certain conditions must be met.

As mentioned above, a vehicle’s 4WD system and its restrictions will depend on its age as well as its make. Some older vehicles must be in the parked position or at least not moving in order to switch to 4WD.

Newer model vehicles tend to have a button you can press or a switch you can move to go into 4WD, while older ones must be shifted into. When looking at the system in your vehicle you may notice a 4H or 4L instead of a 4WD. These stand for 4 High and 4 Low, two different modes of 4WD.

In 4 Low, your tires will receive more torque. While this can be useful in some situations, when stuck in snow or mud it can make matters worse. 4 High can typically be shifted into when driving at low speeds in newer vehicles or when stopped in older vehicles. In order to shift into 4 Low, however, you will first need to put the vehicle into neutral.

If stopping or shifting into neutral is not a safe option at the time you are driving, simply slow down as much as is safe and then make the shift. Keep in mind, 4WD should not be used when traveling at high speeds. Try to stay below 45 or 55 miles per hour when in 4WD.

4WD is designed to give you more traction in conditions where there is little to none. If you are driving on clear, level roads, you should not be using 4WD. Because these roads provide their own traction, using 4WD can lead to drivetrain binding and can ruin your vehicle.

No matter what vehicle you drive, never shift to 4WD when traveling at high speeds or when on dry, level roads. Do your best to slow down and, if possible, shift into neutral to change into 4WD.

What’s the Difference Between 4WD High and Low?

As mentioned earlier, 4WD High and Low serve different purposes. In order to know when to shift into one of these settings, you must first know what they do and why or risk damaging the drivetrain.

For help remembering their purposes and limits, simply look at the name! 4 Low will require the vehicle to travel at lower speeds in order to be effective and to not damage the undercarriage of the vehicle. Try not to use 4 Low when traveling more than 15 miles per hour. The purpose of 4 Low is to help the vehicle when it’s traveling through tough terrain by providing extra torque. This may include crawling through sand, splashing in creeks, and climbing over boulders. 

As for 4 High, this setting is best used on winter roads or when the vehicle is at risk of hydroplaning. When driving in 4 High, you should never exceed 55 miles per hour. Higher speeds are difficult because of the lower amount of torque being provided to the wheels.

“…Well depends on how fast you’re going and what T-case you have. With manual transfer cases you’re supposed to be stopped for 4hi and if you want 4lo you need to shift into neutral. Ford has ESTOF (Electronic Shift On the Fly) where you can shift into 4hi while driving. But once again I think you have to be in neutral or park to be able to shift into 4lo with them.”

-Cole B. (Mechanic)

Advantages of 4WD

• Four-wheel drives offer superior grip and traction over a variety of surfaces.
• Power is also utilized better since all 4 wheels are propelled in 4WD giving you a more sure-footed and confident feel.
• When conquering challenging terrains such as mud, snow, rocks, and other difficult driving environments the 4WD comes into its own by maintaining traction under a variety of low traction surfaces.
• The additional weight of the body actually provides a grip advantage when going off-road.
• 4WD advanced traction affords it the ability to climb out steep uneven hills and slippery mountain tracks a 2WD could never attempt. 
• Power is sent to all 4 wheels which gives a 4WD a huge advantage over a Two Wheel Drive derivative.
• The 4WD capability drastically decreases the risk of the vehicle becoming temporarily immobile. Differentials can be locked for added grip during slippery, uneven, cross-axle terrain, allowing you to drive out.
• Cornering is also superior as the power is equally transferred to all wheels, allowing the load to be reduced on each wheel.
• Engine compression braking is improved as it works in conjunction with the 4WD drive-train allowing you to descend loose slippery surfaces with ease and in full control. 
• Most modern 4WD’s have technology like hill descent control and hill climb assist as a standard.

Disadvantages of 4WD

• Heavy body on frame chassis results in higher fuel consumption
• The body on frame construction is not as safe as monocoque SUV’s (Although the safety of Ladder Frame Utes has greatly improved in the last few years)
• High center of gravity negatively affects your overall MPG and results in higher wind noise inside the cabin
• Bigger longer vehicles are not easy to maneuver and parking in shopping mall lots, as well as city driving, can be tricky in areas where roads are narrow
• Bigger vehicles take longer to stop and slow down
• More components to service make for increased service costs
• More expensive purchase price over 2WD vehicles
• Higher maintenance costs as they are purpose-built and some require specialized components and tools to repair
• Ladder frame 4WD’s do not offer good on-road handling in terms of body roll and cornering dynamics.

All Wheel Drive Advantages and Disadvantages

AWD Advantages	AWD Disadvantages
The vehicles traction is governed and managed automatically	Most modern AWD Cannot drive in 2H if a drive shaft breaks, leaving you stranded.
AWD requires less driver input to maintain traction across a variety of road surfaces.	More expensive to repair
Can drive across a mixed traction surface such as half snow and dry tarmac roads	More drive-line components to service resulting in higher service  costs
Permanently engaged in 4H mode for superior traction	More sophisticated drive-line systems which increase the initial purchase cost
Much better control and traction over 2WD front and rear wheel vehicles in snow and other low traction surfaces
More even tire wear compared to rear and front-wheel drive vehicles
Gives you more confidence to drive faster (55-65+ MPH) in a variety of conditions without concerns of damaging the drive-train system.

AWD VS. 4WD

A Four Wheel Drive (4WD) is optimized and designed for challenging driving conditions like rock-climbing, fording deep rivers, and conquering steep hills with loose, low traction surfaces.  The fact is that many 4WD owners seldom need this extreme capability that a 4WD offers unless you are a serious off-road enthusiast. 

There are multiple reasons why a Four Wheel Drive is beneficial to own. Drivers enjoy increased safety during challenging driving conditions. It does, however, comes at a price since the initial purchase price is higher than a 2WD of the same make. Also, you will get less MPG with a 4WD than a 2WD, so you’ll end up paying at the pumps.

Maintenance costs are higher and it could be a bit challenging to maneuver around shopping mall parking lots. However, it does open up opportunities to explore this beautiful planet with confidence by allowing traction in otherwise undrivable conditions. It provides a sense of adventure and gives you the confidence to drive anywhere at any season of the year.