Off-roading requires drivers to use gears strategically to climb steep banks or extract themselves from boggy ground. Because of this, some manufacturers offer models with two sets of gear ratios: “4 low” and “4 high.” The lower is for off-roading, while the higher is for regular driving.
What Are The Differences Between 4-Low and 4-High?
4-low (as the name implies) is a lower gear ratio that provides more torque at low speeds. It helps vehicles crawl over challenging terrain and obstacles by turning the wheels with more force.
4-high refers to a higher gear ratio for vehicles traveling at faster speeds. This gearing is suitable for light off-roading and regular on-road driving.
Not all 4x4s and SUVs feature 4-low gearings. Manufacturers usually reserve them for the most serious off-road vehicles engaging in rock climbing and mudding.
Vehicles with 4-low and 4-high gear ratios usually have a button that lets you switch between them. Most manufacturers require you to stop your 4x4 before you change the gear ratio. Trying to do it while moving could damage the transmission.
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The vehicle’s transfer case determines how much engine torque the transmission sends to the front and rear wheels. Serious off-road vehicles usually have settings that let you adjust the split, usually 50-50.
The transfer case acts like a second transmission. It works by shortening the gearing and multiplying the torque sent to the wheels (all four on a 4WD vehicle).
Some manufacturers also offer a 2-high option for on-road driving. Here, transmission only sends power to the front wheels to prevent wear and tear on the rear axle.
Vehicles may also have an automatic transfer box. Here, the transmission adjusts gear ratios depending on the terrain. Automatic modes are suitable for wet days and slushy or snowy conditions when driving on the road.
When Should You Use 4-High And 4-Low?
If you are a serious off-roader, learning when to use 4-high and 4-low is critical because it lets you extract maximum performance from your vehicle. Many drivers can traverse the ground better when they change settings, making the driving experience more fun.
Here’s what to do:
- Use 2-high when you are driving along regular pavement at higher speeds in normal (non-slippery) conditions
- Use 4-high when you are driving in slippery conditions, either on-road or off-road
- Use 4-low when you encounter the most challenging terrain, such as rock climbs, muddy bogs, rivers, and deep snow
Most 4x4 drivers prefer to keep their vehicles in 4WD mode all the time because it provides additional traction and stability. Cars feel more planted and secure than regular two-wheel-drive alternatives.
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Vehicles in 4WD mode are also ready to take on unanticipated challenges when they arise. Drivers don’t have to stop their cars to change settings, which could be inconvenient.
Please note that you shouldn’t use 4-low for high-speed driving, especially at speeds of more than 35 mph. Doing so could result in damage to your vehicle and costly transmission replacements.
Note also that not all SUVs feature a 4-low option. Therefore, choose your make and model carefully if you want this feature. Avoid purchasing 4x4s designed for the school run.
How To Engage 4 Low Gears
If you decide to use your vehicle’s low gear range, it’s wise to set it up first. Here’s what to do:
Step 1: Configure Your Tire Pressure
Start by lowering the tire pressure to a level suitable for the terrain. Professionals use 15 to 20 PSI for sand dunes and 20 to 25 PSI for mud and rocky surfaces.
Some situations require you to drop pressures lower. Reducing PSI below 15 increases the contact area between the tire and the terrain, offering more grip. However, it also increases the risk of wheel rim damage, particularly when going over drops or rugged ground.
Step 2: Park Your Vehicle
The next step is to park your 4x4 and move the gear stick to “park” or “neutral.” Shifting to this position allows the transfer case to change the gear ratios and torque to the front and rear wheels.
Step 3: Use Your Button Or Dial To Switch To 4 Low Mode
Next, you’ll need to use a dial or button on your vehicle to switch to 4-low mode. The appearance varies according to the manufacturer, so always check your vehicle’s handbook.
Once you press the button, you should notice an indicator light on your instrument cluster, usually “4L” or a close variation. When it appears, 4-low is ready to use.
Step 4: Shift Into First Gear
Once you’re sure the transmission is in 4-low mode, put your foot on the brake and shift into first gear. You should notice you have more traction than before to tackle the terrain.
Once you activate 4-low, you don’t need to do much more than watch your vehicle’s wheel placement. If you drive a Jeep, Toyota, GMC, or Land Rover, you should now find it easier to traverse along muddy banks and up steep, rocky hills. You should also notice the engine requires less revving for the same effect.
In summary, 4-low and 4-high are different gear ratio settings on 4x4 vehicles. 4-high is for regular driving and mild off-roading, while 4-low is better for the most intense overlanding situations.
You shouldn’t use 4-low on the highway or at high speeds because it can damage the transmission and transfer box. Likewise, avoid using 4-high when traversing rivers, mud, bog, marsh, sand dunes, rocks, and steep inclines. It might not provide enough power, leaving you stranded.
Regardless of your transmission, getting stuck is inevitable for off-roaders. At some point, you will strand your vehicle and need a winch or rope to pull it out.
Fortunately, Rhino USA offers a range of recovery kits and gear to help you out of sticky situations, including kinetic ropes, tow straps, and folding survival shovels. Products are made to the highest quality and come with a lifetime warranty.