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Semi Truck Drive Trains: 18 Important Facts You Should Know!

Every time you talk about whether a semi truck is an AWD, 4WD, RWD, or FWD, you’re referring to a vehicle’s drivetrain.

A drivetrain is composed of all the components necessary to transmit the engine’s energy to the wheel so the vehicle can move.

In this article, you’ll learn about drivetrains, their purpose, and how they work. 

Here is a short summary of Semi Truck Drivetrains:

A drivetrain is a group of vehicle components that supplies power to the wheel through the engine. Drivetrains have 4 various layouts such as AWD, 4WD, RWD, FWD. The name of the drivetrain implies which wheel is powered. For instance, all wheels are powered in AWD, rear wheels for RWD, and front wheels for FWD. 

What does 6×2, 6×4, 6×6 in a Semi mean?

6×2, 6×4, and 6×6 are 6-wheel axle configurations. These are drivetrains that determine which type and level of performance a truck can provide. 

For a long time, the standard configuration of semi trucks has been 6×4 and 6×6. Historically, many truckers prefer these configurations. 

However, some drivers and fleets have been switching to 6×2 lately.

A 6×6 configuration features three axles as drive axles. This is perfect for off-road with average to moderate haulage. It focuses on the traction and mobility of a vehicle.

A 6×4 configuration has two rear axles as drive axles. This is preferred if a truck operates off-highway or during inclement weather conditions.

Meanwhile, a 6×2 has two rear axles, with only one of them receives power. This configuration is your best bet for fuel efficiency. It’s ideal for line-haul operation in icy or slippery road conditions. 

Are Semi Trucks All Wheel Drive?

In general, semi trucks with all-wheel drives have a 6×6 drivetrain configuration. All-wheel drive semi trucks are used in heavy-duty and offroad applications such as the building and construction industry. They are excellent for heavy load carrying but as not as fuel-efficient.

Generally, a 6×6 is an AWD drivetrain configuration. The AWD system can operate with too little input from a semi truck driver, whether part-time or full-time. 

In part-time AWD, the wheels receive torque from the vehicle’s components such as differentials, multi-plate clutches, and viscous coupling.

The system works with two wheels when the road situation needs extra traction.

In full-time AWD, the rear and front axles are driven at the same time. 

This type of AWD system makes handling the truck easier for the driver. It ensures that full power is being utilized while on the road.

How do you know if your Semi Truck is All-Wheel Drive?

Your semi truck is an all-wheel-drive if it has all its axles driven by the driveshaft. The driveshaft will run transversely underneath the truck connecting all axles.

To know if it’s an AWD, check your vehicle’s manual. The information needed is listed in the features. If nothing is mentioned, your truck is probably not an AWD.

Look underneath the car if you lost the vehicle’s manual or bought a second-hand truck without the manual.

Check the presence of the axle shaft located between the front and rear axle. The axle shaft looks like a large bar object. If the axle shaft is mounted on the location mentioned, the truck is an AWD.

What are all Wheel Drive Semi Trucks good for?

The best thing about AWD is that there’s no need for drivers to engage much with the system. 

It’s either the wheels are driven full-time, or they automatically deliver power when needed.

AWD can operate in various road and weather conditions, whether smooth, off-road, slippery, or snow season. 

However, this drivetrain is not the number one choice for truck operators regularly working in off-road conditions.

AWD is more helpful in highways and streets than in off-road adventures.

What are the Popular All Wheel Drive Semi Trucks?

Volvo is the most famous brand in the AWD category.

It’s the first brand to offer AWD features among all the trucking manufacturers in the world.

Here’s a list of the most popular AWD drive trucks:

  • Volvo VNL 300 and 400
  • Volvo VNX series
  • Kenworth T8800
  • Freightliner M2 106
  • Peterbilt 567 AND 348

Are Semi Trucks 4 Wheel Drive?

In general, heavy-duty semi trucks used for commercial purposes are 4 wheel drives with a 6×4 drivetrain configuration. Semi trucks with 4 wheel drives are great at carrying heavy loads and are more fuel-efficient. This is because the load rests on the rear tires, offering more traction on the road.

4WD system is more vigorous than AWD. 

It can handle better in rugged terrain. 

They are also of two types such as full-time and part-time 4WDs.

A full-time 4WD drivetrain receives power consistently. In most semi trucks, a driver can control the power apportioned in both rear and front axles.

A part-time 4WD is more common in SUVs and trucks designed for the harshest off-road condition. It’s driven mainly by two wheels in the rear. There’s also a differential that the driver can use for extra traction.

How do you know if your Semi Truck is 4 Wheel Drive?

Besides looking at the vehicle’s manual, there are many ways to determine that your truck is 4WD.

The easiest method is to check the manufacturing date. If the manufacturing date is in the early 2000s, it’s probably not a 4WD but RWD.

To be sure, take a look at the gearbox. Typically, a 4WD doesn’t have an auxiliary gearbox for the driveshaft. 

Also, a drive shaft will connect both the drive axles transversely. Typically in a 6×4 semi truck, the 2 rear axles will be connected by the drive shaft.

Moreover, by only looking at engine architecture, you can identify if it’s a 4WD. To do this, locate the drive belts inside the engine. If the latter is facing to the side, it’s a 4WD. 

What are 4 Wheel Drive Semi Trucks Good for?

Semi trucks that are 4 wheel drives have a 6×4 drivetrain configuration. Traction and power are significant assets of 4WD. 

If you have seen a truck climbing in a rocky and steep hill in TV commercials, that’s probably a 4WD in action.

4WD is designed on extreme road and weather conditions. 

So if the truck operates in remote areas, 4WD is recommended. It can withstand off-road adventures and extreme weather conditions.

There are few compromises in fuel efficiency, though. 4WD is not that cost-effective in terms of fuel. But overall, if you like to control your truck, 4WD is a great choice.

What are the Popular 4 Wheel Drive Semi Trucks?

Most popular semi truck brands have 4WD units in their name. 

The best-sellers are the following:

  • Freightliner M2 Sport Chassis
  • International Lone Star, MV Series, and Transtar
  • Volvo VNR Series and VNL Daycab
  • Peterbilt 359

Are Semi Trucks Rear Wheel Drive?

In general, semi trucks are rear-wheel drives with either a 6×2 or 6×4 drivetrain configuration. The rear wheels of the semi truck are responsible for carrying the load. This makes for excellent traction for the tires on the road since the weight of the load is on the rear wheels.

RWD is a type of drivetrain having more precise control in driving conditions. Through the engine, most power is transferred to the rear wheels.

Both the rear and front axle RWD works hand in hand to provide top-notch performance to the wheels. The rear is responsible for the overall power, while the front works on the steering system.

RWD is also designed for better weight distribution. Like AWD, this drivetrain is commonly used on-road. Expect the risk of sliding off or losing control when using RWD on a slippery road.

How do you know if your Semi Truck is Rear Wheel Drive?

In determining whether your truck is rear-wheel drive, you can use the same method for 4WD. Check the manufacturing date or the engine.

If the semi truck is manufactured as early as 2010 and below, it’s most likely a rear-wheel drive. 

For the second method, check the placement of the drive belt in the engine. As mentioned, the drive belt for 4WD must face sideway. Whereas for RWD, the belt should face to the front.

What is Rear Wheel Drive Semi Trucks Good for?

All in all, RWD is good for hauling, towing, and delivering goods and cargos. 

This is because the weight of the cargo is closer to the rear. And RWD has more substantial power in its rear wheels.

Since the weight is distributed correctly, the driver can better handle the steering system and the semi truck overall. 

The front wheels handle the steering while the rear wheels work on the driving.

That said, wheels in RWD can provide optimum performance because they don’t interfere with one another.

The only disadvantage of RWD is when it’s used in harsh weather conditions like snow or the rainy season. It provides less traction, and the steering system function is compromised.

What are the Popular Rear Wheel Drive Semi Trucks?

Since the 20th century, semi truck companies are already selling RWD trucks. As such, it’s not difficult to find the best RWD trucks out there.

Here are the most popular brands and models:

  • International LT Series
  • Volvo VHD Series
  • Kenworth K100, T270, T370
  • Peterbilt 389
  • Freightliner M2 112

Are Semi Trucks Front Wheel Drive?

There are semi trucks that have front-wheel drives (FWD), they are few in numbers. Front-wheel drive semi trucks are typically used for hauling lighter loads. FWDs are inefficient for heavy-duty applications as the front tires don’t get sufficient traction when the load is resting on the rear tires.

How do you know if your Semi Truck is Front Wheel Drive?

Your semi truck will have a drive shaft connected to the front axle only.

This configuration would have existed in older semi truck models and nowadays in smaller trucks.

What is Front Wheel Drive Semi Trucks Good For?

Front-wheel drive vehicles are typically used for higher-speed applications and less heavy-duty hauling.

If you are carrying lighter loads, then a FWD will be much more fuel-efficient due to power being transferred to the front wheels only.

Which Drivetrain should you go for when Buying a Semi Truck?

Overall, there’s no such thing as the “best” drivetrain. 

The best choice should depend on your needs, preferences, and cargo capabilities.

This table might help you choose the best drivetrain for a semi truck.

Semi truck Drive Trains6×26×46×6
Off-roadPoorOkay Good
Extreme weather conditions (Icy roads)Poor Okay Good
Improved traction and controlPoor Good Good
Fuel EfficiencyGood OkayPoor
Heavy-duty haulingPoorGood Good
Light-duty haulingGood Good Good
AffordabilityGood OkayPoor