What Are 2H, 4H, and 4L on 4×4? 

Your truck or SUV has higher ground clearance and more capable suspension to help you get through challenging terrain. Whether it’s for off-roading or winter travel, you might also want a 4x4 system that gives even more traction. Four-wheel-drive models typically have a 4WD selector switch, lever, buttons, or a knob to change the 4x4 modes with settings like 4LO, 4HI, and 2HI. What’s the purpose for each setting, and which should you use?

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Why Are There Different Modes for 4WD? 

With trucks and SUVs equipped with 4WD, you’ll have different drivetrain modes to allow you to choose the most appropriate level of traction and stability for the driving conditions. Different modes are designed for different types of terrain and driving situations, and each mode can provide different levels of traction and stability. 

But why wouldn’t you want to drive in 4WD all the time? There are two main reasons: fuel economy and strain. When your vehicle is in 4WD, the drivetrain has to send torque to both the front and the rear drive axles or differentials, and that commands more power, thus, more fuel is burned. If you don’t need enhanced traction, turning off 4WD will save on fuel. 

And when all four wheels are engaged unnecessarily, there’s a possibility for excessive wear and tear or damage. Your tires might ‘scrub’ while turning, wearing them down faster, and turning on dry pavement can make it feel like the drivetrain is binding, stressing all the components from the driveshaft and transfer case to the axle shafts and U-joints. 

What Does 2H Mean in 4x4s? 

Four-wheel drive mode, on the other hand, is designed for off-road driving and provides additional traction and stability when driving on rough terrain.

In the context of 4×4 vehicles, 2H refers to a drivetrain mode that allows the vehicle to be driven in two-wheel drive. This means that power is only being sent to either the front or rear wheels of the vehicle, rather than all four wheels. 

Typically, 4×4 vehicles have the ability to switch between two-wheel drive and four-wheel drive mode. In two-wheel drive mode, the vehicle is typically more fuel efficient and can offer a smoother ride on paved roads. Four-wheel drive mode, on the other hand, is designed for off-road driving and provides additional traction and stability when driving on rough terrain. 

What is 4H in 4X4s? 

4H, also called 4HI or 4 HIGH, refers to a drivetrain mode that allows the vehicle to be driven in four-wheel drive. This means that power is being sent to all four wheels of the vehicle, providing additional traction and stability when driving on rough terrain. 

4H provides better traction and stability on uneven or slippery surfaces. It can also be useful in situations where the vehicle may become stuck, such as in mud or snow. 

To engage 4H, all you’ll do is press the 4H or 4HI button or turn the switch. Behind the scenes, the transfer case engages the front driveshaft so it no longer freewheels but matches the revolutions as the rear wheels. 

What Does 4L Mean in 4x4s? 

4L, meaning low-range four-wheel drive, is a specialized mode that is designed for very slow, controlled driving on rough terrain or in situations where the vehicle may become stuck. Although it’s seldom used, it’s an important mode if you ever put your vehicle to the test. 

When the vehicle is in 4L mode, the transfer case is geared differently than in normal four-wheel drive mode. This allows the vehicle to crawl at very low speeds, which can be useful for navigating steep inclines or descents, or for pulling the vehicle out from being stuck. 

What Does AUTO Mean for 4WD? 

Does your 4WD switch have an AUTO setting? It refers to an automatic transfer case mode that allows the vehicle to automatically switch between two-wheel drive and four-wheel drive while you’re driving, depending on the driving conditions. 

When the vehicle is in AUTO mode, the drivetrain is designed to detect when additional traction is needed, such as when driving on slippery or uneven surfaces. If the vehicle’s computer system determines that additional traction is needed, it will automatically engage four-wheel drive. When driving on paved roads or in normal conditions, the drivetrain will typically operate in two-wheel drive mode to save fuel and provide a smoother ride. 

Which 4×4 Mode Should You Drive In? 

Clearly, using 2HI when the road conditions are clear and the surface is unbroken will be best. But when the conditions deteriorate, how do you decide between 4 Low vs 4 High? Here are a few scenarios: 

  • If the freeway has become slippery with a dusting of light snow, 4HI is the right option. 
  • If your backlane or side roads are caked with snow and ice, 4HI is still the best choice to get through them at low speeds. 
  • If you’ve slid off the road and can’t drive out normally, 4LO might help get enough traction to get out. 
  • If you’re driving a challenging off-road course, climbing a steep embankment, or playing in the mud, 4LO is probably best. 

Luckily, if you can’t decide 4H vs 4L, you can always try 4HI first and, if it doesn’t get you the traction you need, you can switch to 4LO. 

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