Exploring the Power of 4-Wheel Drive: A Comprehensive Guide

A well-known 4-wheel drive expert on social media once asked: “What does four-wheel drive mean to you?”

The strange part was, that the more I thought about it, I realized that the question might be simple but the answer is rather complex.

With that being said, With all my 20+ years of 4-wheeling experience and have owned over 9 different 4x4s of various makes and models, the first thing that comes to my mind when I think of 4WD is that it’s at the pinnacle of power, capability, and versatility, but only when used correctly…

This article will further unpack the definition of the power of 4-wheel drive, and explore its mechanics, proper application, benefits, and proper usage.

Let’s now look at how four wheel drives help…

The Power of 4-Wheel Drive Explained

Four-wheel drive, 4-wheel drive, 4WD, and 4×4 are all terms referring to the same type of drivetrain.

A 4×4 is a type of vehicle equipped with a drivetrain that sends engine power and torque to all 4 wheels simultaneously or when decided by the driver.

A 4×4 drivetrain offers many advantages such as superior traction, off-road abilities, and enhanced control on a variety of surfaces.

This gives the driver the ability to tackle many off-road or overland adventure tracks with confidence.

Modern 4-wheel drive vehicles come in a variety of forms with manufacturers sporting different names, however, there are basically only 2 types of 4×4 systems and they are:

1. Permanent 4×4
2. Part-time 4×4

Both versions have their advantages and disadvantages, which we will discuss next.

Permanent 4×4 Explained

A permanent 4×4 means the engine always sends power and torque to the front and rear axles.

The power is split 50/50 between the front and rear axles thus offering improved traction and control on a variety of surfaces.

A permanent 4×4 has no 2H function which only powers the rear wheels.

A permanent 4×4 is always in 4H.

• When driving on more challenging surfaces with a permanent 4×4, the driver can select 4H-L to lock the transfer case thus joining the front and rear driveshafts to rotate as a single unit.
• When 4H-L is selected 50% of the power is sent to the front axle and 50% to the rear axle.
• The 50% of the power is then split on the axle and sent to the wheel with the least resistance.

Part-time 4×4 Explained

A part-time 4×4 means the vehicle is predominantly driven in 2H when driving on high-traction surfaces such as dry pavement and on the highway in the city.

A part-time 4×4 relies on driver input to select 4H once he determines he is driving on a slippery, low-traction surface.

• A part-time 4×4 should not be driven in 4H on a high-traction surface such as dry pavements or highway driving since it eventually causes drivetrain binding.
• When 4H is selected on a part-time 4×4 the transfer case locks the front and rear driveshafts.
• Engine power and torque are split 50/50 between the front and rear axles.

4×4 helps because it allows you to drive on slippery low-traction surfaces with a decent measure of control.

It also allows you to drive on uneven, challenging terrain where a normal vehicle with only 2H cannot.

4×4 helps you to drive on low-traction surfaces such as:

• Snowy roads
• Gravel/Dirt roads
• Icey highways
• Sand dunes
• Rocky roads
• Wet roads

Next, let’s look at the maximum time we should drive in 4WD

How Long Should You Use 4-Wheel Drive?

This was something that concerned me when I bought my very first 4×4 and was still very new to the whole four-wheel driving scene.

So, how long can I drive in 4-wheel drive? The answer is… as long as you need to.

The fact is, there is no maximum time limit or maximum distance when you drive in 4WD as long as the road surface conditions are suitable for 4WD 4H to be engaged. i.e.

• Slippery roads
• Dirt roads
• Excessively wet surfaces
• Snowy surfaces
• Icy roads
• Sand
• Muddy tracks
• Grass etc.

For example, you are on a multi-day off-road expedition, and I have first-hand experience where we spent the entire day, for multiple days driving in 4WD mode.

If road surface conditions are too slippery, or you’re driving on thick beach sand, or rocky dirt tracks then you will need to remain in 4WD which is perfectly fine.

There is absolutely no risk of damage to your drivetrain if the road surface is bad. Driving in these conditions in 4H offers improved control, and traction, and is less demanding on your engine, chassis, and drivetrain system.

Next, let’s look at how 4WD affects your stopping ability.

Does 4 Wheel Drive Stop Faster?

This is an interesting question and the answer is actually two-fold. In the first part, I will discuss if a 4 wheel car (4×4) stops faster than a two wheel car (4×2) under normal driving conditions.

The second part I will cover is if a 4×4 stops faster when 4H or 4Lo is engaged compared to when driving in 2H with your 4×4.

Does a 4×4 stop faster than a 4×2

So let’s get into it, does a 4×4 stop faster than a 4×2 of the same make and model?

Also, let’s for the sake of the article assume all variables are the same i.e. tires, weight, brake discs, etc. In this instance, the answer is, NO.

That is simply because a 4×4 carries more weight and has a higher TARE weight than a 4×2 of the same make and model.

• The additional drivetrain components like the transfer case, front diff, front axle, side shafts, driveshafts, etc all contribute to the vehicle’s Tare weight.
• The additional weight from the 4×4 components increases the vehicle’s TARE weight and thus makes it harder to stop.
• In this case, it would be safe to say a 4×2 would stop quicker than a 4×4 since it is lighter and thus stops quicker.
• The 4×4 drivetrain does little to nothing when it comes to stopping.

Does a 4×4 Stop Faster When in 4WD (4H or 4Lo)

Now let’s look at the second scenario where we want to establish if a 4×4 stops faster when four wheel driving (i.e. 4H or 4Lo is engaged) compared to when driving in 2H with your 4×4.

In this case, I would say yes, when 4WD is engaged the vehicle will stop quicker since all 4 wheels contribute to slowing the vehicle down since it will utilize the drivetrain and engine compression to assist the brakes.

• When the truck is in 4H or 4Lo, the driver can also make use of the engine compression to help slow the vehicle down.
• The engine braking technique is recommended when ascending down steep uneven tracks for extended periods since it will assist the brakes and avoid brake fade.
• By doing this the wheels will only rotate as fast as the engine allows in the lowest gear you are in and the two will work together to slow the vehicle down in a controlled manner.

Does 4WD Use More Gas?

So this question is two-fold with the first part focusing on MPG when comparing a 4×4 to a 4×2 of the same make and model and the second part when engaging 4WD in an off-road situation where your truck uses more gas.

So let’s start with the first part, does a 4×4 use more gas than a 4×2 of the same make and model?

Yes, a 4×4 will use more gas since it has more drivetrain components and the overall TARE weight is heavier when compared to a 4×2 of the same make and model.

4x4s have additional components such as but not limited to the following:  

• an extra differential
• a transfer case
• a front driveshaft.
• Additional u-joints
• Additional suspension components
• Additional supporting brackets
• Additional chassis strengthening

These components are quite robust and heavy and add to the overall tare weight, friction, and rotational mass which negatively affects fuel consumption on the 4×4 derivative.

Does 4×4 Use More Gas When Four-Wheeling

The second part of the question is, does 4×4 use more gas when four-wheeling (i.e. 4H or 4Lo is engaged) compared to when driving in 2H?

The answer is yes since 4H or 4Lo engages more components that are usually not engaged when driving in 2H.

Components such as the transfer case gears, the front driveshaft, the front axle, the output shafts, and more.

All these additional components add resistance to the drivetrain system which results in your engine using more gas.

• When 4Lo is engaged, this is when your MPG takes a real knock.
• This does not necessarily mean your 4WD is using more gas, it simply means you are getting less MPG because of the low ratio gearing.
• When 4Lo is engaged it uses much lower gear ratios and this results in higher revs which means less MPG.
• Also, the wheels are rotating a lot slower when compared to driving in 4H or 2H for the same amount of revs.

So, yes your truck will get less MPG when driving in 4WD.

Forum User Experiences & Opinions

User Opinion #1

The question isn’t how far you could drive – if you were on a long enough dirt road you could drive as far as the road went in low.

The problem is when you drive 4wd (locked) on hard pavement. Locked 4×4 with a standard transfer case requires 2 or 4 wheels to turn at the same speed.

Normally when turning on pavement, the outside wheel turns more than the inside wheel, and the front and rear wheels need to be able to turn at slightly different speeds as well due to variations in tire size and road surface, etc.

Being “locked up” on hard dry pavement puts stress on the drivetrain.

Driving fast just makes these problems worse.

So let’s say you’re on a trail, and you forget to unlock the 4wd – either locking hubs (remember those?) or the transfer case.

Within a short time – 100 yards, maybe 1/4 mile – you’d start to feel the steering get strange, possibly “judder”, or you’d hear tire squeaking as the drive tries to adjust.

At this point it might actually be hard to unlock the transfer case.

Modern all wheel drive vehicles such as the Subaru, Audi, or Range Rover have full time limited slip transfer cases which don’t have the same problem.

They are designed to be in four wheel drive all the time.

Some do have a locking transfer case – and this will cause problems if left locked.

Low gear is just low gear. You can drive far, but you can’t drive fast.

https://www.quora.com/How-far-can-I-drive-my-4WD-while-still-on-high-or-low

User Opinion #2

Leaving 4wd on when you have good traction is gonna cause premature wear. Leaving it locked is just asking to break something.

I’m surprised the steering doesn’t bother him.

I only use it for snow, mud pits, and steep slopes with loose rock.

4Lo for engine braking on steep downhills.

https://www.reddit.com/r/4×4/comments/7somsq/how_often_do_you_actually_use_4wd/

User Opinion #3

Lower parasitic power loss trying to drive 4 wheels instead of two, as the power has to be transmitted from the transmission into a transfer case and front/rear differential.

This power loss is due to rotational weight, and most importantly friction.

Don’t use 4wd mode, less friction, less power being used to drive the extra wheels… slightly better fuel economy.

How much? we cant tell you because your driving habits are different and can vary day to day.

But as a guide, the difference is something that can be as high as 10mpg.

https://www.reddit.com/r/cars/comments/5kmu71/does_putting_my_car_in_allwheel_drive_mode_use/

Helpful Resources

• https://www.quora.com/How-far-can-I-drive-my-4WD-while-still-on-high-or-low
• https://www.reddit.com/r/4×4/comments/7somsq/how_often_do_you_actually_use_4wd/
• https://www.reddit.com/r/cars/comments/5kmu71/does_putting_my_car_in_allwheel_drive_mode_use/

Final Thoughts

In conclusion, four-wheel drive offers many benefits for off-road and overland adventures.

It provides superior traction, control, and stability on various challenging terrains such as snowy, icy, or muddy surfaces.

While engaging 4WD can result in higher fuel consumption the trade-offs are outweighed by the increased safety and capability in demanding environments.

It’s essential for drivers to understand the mechanics of 4WD systems and when to use them to fully harness their potential and navigate challenging conditions effectively.

By making informed choices and mastering 4WD techniques, adventurers can unlock a world of exploration and confidently embrace the outdoors.