Having a 4-wheel drive gives you a feeling of safety, especially when driving through rough paths. Luckily, a 4WD delivers equal power to the four wheels, increasing your chances of overcoming obstacles.
Thus, GMC 4-wheel drive SUVs can get you out in difficult conditions. But only a good driver can maximize its potentials. Hence, this article focuses on how to engage 4-wheel drive GMC Sierra.
Follow our guide to get a hank over your Sierra 4WD settings.
What makes the GMC Sierra SUV special?
The GMC Sierra 4 Wheel Drive is one of the most powerful trucks today. What makes this truck unique is how it transmits the vehicle’s power to the four wheels, preventing slip and traction loss.
This SUV is pretty useful in slippery, steep, and muddy surfaces, but only when you know how to engage it.
What are the basics of a 4WD drivetrain system?
You may have heard about the 4WD but yet to understand how it works. Primarily found on trucks and SUVs, 4-wheel drivetrain transmits equal power to the four wheels.
As mentioned earlier, what separates the 4-wheel drive SUVs from other vehicle types is the power and traction. Let’s discuss them.
Your engine’s rotational power is called torque. Meanwhile, the drivetrain has to transfer the torque to the wheels for the car to move.
But your tires must have traction on the road before your vehicle moves. Of course, no matter the torque delivered to your wheels, the car can only move if there is enough traction. Instead, your tires spin, but the car goes nowhere.
So, traction utilizes the engine’s torque to move your car.
Now, a 4-wheel drive’s role is to increase the truck’s traction whenever you drive on a slippery surface. You’ll notice it’s easier to drive off with a 4WD than a 2-wheel vehicle.
So, increased traction is one of the most significant benefits of a 4-wheel drive truck.
Another outstanding benefit of any 4WD is increased power transmission to the wheels. Sometimes traction becomes less important when you’re faced with an obstacle on the road.
At this time, what you need most is extra power transferred to the wheels. Of course, this is where the 4WD system wins.
What’s more, many 4-wheel drive vehicles have designs that allow you to shift between high and low 4WD modes easily. The high mode transmits full power to the wheels when driving on a dicey terrain, without sacrificing speed.
But the low-range 4WD setting reduces the speed to the wheels but supplies enough power to ride over the roadblock.
The next section talks about the common driving modes in the GMC Sierra truck.
What is the GMC Sierra 4WD Driving Modes?
Besides buying a new truck, understanding your vehicle’s settings will boost your confidence when plying a difficult route. Besides, knowing and applying proper 4WD engagement techniques prevents damage to you and the vehicle.
First, let’s discuss the GMC Sierra driving modes.
Mode 1 – Two Wheel Drive
When driving on normal roads, operating your 4-wheel drive vehicle as 2-wheel reduces wear and tear on its components. If the road condition is good and you’re not faced with traction loss, you can use the 2drive setting.
Here, the power enters the transfer case before being distributed to the rear axles and wheels. Sometimes 2-wheel drive does not improve traction, but you can use it in any environment.
This 2-wheel drive setting, masked 2↑ is your GMC Sierra default mode. Unless you’re going through rough terrain, try to keep your vehicle in the 2-high mode.
Mode 2 – Four-Wheel Drive (High Range)
GMC High Range mode with a 4↑ sign is best for soft or slippery paths. This setting engages the front axle while transferring power from the two axles to the four wheels. The 4↑ causes the front and rear axles to rotate at an equal speed.
But you can still experience a slight speed change because of track length and tire size differences. Called ‘crow hop’, this speed change creates huge competition between the front and rear axles, forcing the tires to slip.
Luckily, GMC SUVs have a unique transfer case design that allows drivers to easily shift between 4-wheel to 2-wheel drive to stop the vehicle.
For trucks with electronic transfer cases, the light on the selector knob flashes when engaging the shift but stops when completed. However, an LED found in the gauge cluster flashes if your truck uses a manual transfer case.
It’s worth mentioning that High-range mode is not suitable for smooth surfaces with good traction. Still, using it on a dry road places much stress on your drivetrain components, resulting in vehicle damage.
Thus, make sure you change to 2↑ settings once you’re on a smooth road.
· Mode 3 – Four-Wheel Drive (Low range)
The GMC Sierra SUV also comes with a low range 4-wheel drive setting, with a 4↓ marking. This setting increases the wheels’ torque, making it safe to ride on off-road courses like deep sand and mud.
Again, this mode allows you to control the vehicle’s speed in obstacles. It also enhances the effectiveness of the braking components, preventing overheating and damage.
The 4WD low-range is only suitable for rough paths and should never be utilized at speeds over 45 mph. What’s more, it takes a little effort and technique to shift into a low-range 4WD.
Here, it would help if you started by shifting the transmission to neutral to remove the torque for a smooth gears shift.
We recommend keeping the vehicle around 3 to 5 mph if your truck uses a manual transfer case. That’s to allow proper gear teeth alignment before you engage the 4WD low-range setting.
Meanwhile, you can return the transmission to drive after successfully engaging the low-range four-wheel-drive mode. Again, the same procedure applies when you want to shift from low-range to high-range.
Make sure you shift out of low-range drive once the road’s condition improves.
· Mode 4 – Automatic Four-Wheel Drive
The automatic setting is perfect for people living in areas where the road alternates between rough and smooth paths. This AUTO setting prepares your vehicle for extra traction, sending more torque to the front axle.
While the front axle remains engaged, the transfer case sends the regular power to the rear wheels. Here, you notice that the clutches regulate the front wheels’ power to enhance the truck’s stability and traction.
The best part is you can use this AUTO setting on any road without damaging your vehicle.
How to engage 4 Wheel Drive GMC Sierra
Here is a quick guide on how to engage 4-wheel drive GMC Sierra when driving on dicey terrains.
Turn on the vehicle using the key.
Put your Sierra SUV in drive or reverse mode and continue to drive until you get into a rough or slippery road.
Check the road condition and pick a suitable 4WD setting. As mentioned above, the 4WD high-range slows the truck for better traction and grip. So, this comes in handy when driving through icy or snowy paths.
Meanwhile, the 4WD low-range is perfect for off-road conditions. Here, it transmits more power to the truck to help overcome the steep.
Possible Problems with driving a 4WD Truck
You need the right skill and information to drive the Sierra 4WD truck on any road condition. First, you should only use the 4WD mode when you need extra traction.
To improve your understanding of the subject, let’s see what happens to your wheels when you make a turn.
Inside and Outside Wheels
Anytime your car turns, the outside wheel goes further than the inside. To match the speed difference against the inside wheel, the one outside spins a little faster, creating a slip differential.
Now, let’s consider a situation where you keep the two wheels locked but spinning at equal speed. As expected, the result is that the inside tire will skid to keep the axle moving.
This won’t cause a scare when you drive on muddy or snowy roads because the tires already need more traction. In this case, the tires can slide without a problem.
So, when does it become a major problem?
It becomes an issue when you make a turn on a paved road with a locked differential. Remember, the outside wheel is moving fast, trying to synchronize with the inner wheel. But it can’t because both wheels are still locked.
So, the external wheel must skid to maintain a speed balance. Meanwhile, the skidding causes the tires to wear because of excess traction on the road. Besides, the skidding also adds more stress to your vehicle’s axle.
Front and Rear Wheels
Another vehicle part that receives significant stress whenever you turn is the front and rear wheels. Of course, the front axle wheels cover a longer distance than the rear wheels.
The front wheels try to spin a bit faster to maintain speed. If not, the rear wheels skid to keep the axle shafts moving.
Meanwhile, this isn’t a big issue with a 2-wheel drive vehicle because the stationary axle allows the front wheels to spin freely. But there’s a problem when you turn with a 4-wheel drive.
Remember, when you engage a 4-wheel drive, the transfer case keeps the front and rare drive shafts locked for equal power transmission.
In other words, the front wheels want to drive faster while the drive shaft wants it to keep the same pace with the rear wheels. Of course, this causes a rift between the wheel pair.
So, how can you end this tension when you engage your new GMC Sierra?
To clear this rift, you should allow the rear tires to slip and slide freely. Of course, this happens when you turn in low traction environments though you have little control over it.
That’s because there’s enough freedom for the front wheels to slip.
Meanwhile, this ‘free spin’ is absent when you turn on a paved path with ample traction. Here, the tires won’t slip, creating a tension between the front and rear wheels.
GMC 4WD Sierra Driving Tips
- The low-range 4WD is unsuitable for paved roads because it adds extra stress to the drivetrain components.
- It’s not a rule that your vehicle must be in drive or reverse settings to engage any of the 4WD modes. However, the ignition must be on, and you can shift to the 4WD mode while the vehicle is in the park.
- Make sure you don’t speed more than your vehicle can handle. The best thing is to slow to maintain grip and control. We recommend you stick to momentum when going through slippery surfaces. Again, when you approach a rough or steep terrain, slow down and leave everything to the truck’s momentum.
- Inspect your vehicle and ensure its functioning properly before hitting the road.
- It’s true your GMC Sierra can handle tough roads, but you should have foreknowledge of your ride area. So, get a map, watch videos, ask about the environment, and Google the weather forecast. Of course, all these prepare you for the journey, especially about speed applications and the best obstacles overcoming skills. Remember, road conditions could change over time; hence, it doesn’t matter whether you took the route before.
- Surprisingly, the lower your tire air pressure, the better. That’s because low air pressure allows your truck to have greater contact with the road. It means the traction increases, making it easy to navigate sand, slippery, muddy, snowy, and rocky terrains.
How does GMC 4-wheel drive work?
The high-range 4-wheel drive works best on slippery surfaces. Here, the front axle steps into action, while maximum power is transferred to the four wheels.
What part of the drivetrain do you shift to engage 4-wheel drive?
When you engage a 4WD, the transfer case sends equal torque to the front and rear driveshafts. Next, the front and rear shafts spin simultaneously, transferring power to the front differential.
Now, the differential transfers torque to the front wheels through the axle shafts.
Can you switch from 2WD to 4WD while driving?
Newer 4-wheel drive models feature an electronic push button that lets you switch while driving.
Is it bad to drive in 4WD auto?
Driving in 4-wheel drive auto is perfect for any road situation. That’s because it only engages when needed and won’t damage your truck.
A 4-wheel drive keeps you safe whenever you hit an unfamiliar path that’s unpaved or slippery. However, you can only enjoy the benefits of your 4WD truck if you can apply its drive modes when necessary.
Remember, no matter how good your GMC Sierra is, you won’t have a nice trip if you miss these rules. Before you hit the road again, try to relearn how to engage 4-wheel drive GMC Sierra when driving on tricky roads.