You might have heard about a car drivetrain and wondered what it was, what it is good for and how you should maintain it. In this article, we will break down all the basics to make this integral part of your vehicle easier to understand.
What is a Drivetrain?
The drivetrain isn’t one part of your vehicle, but a series of components that work together with one mission. The goal is to transfer rotational power produced from your engine so that the wheels move.
Car drivetrains come in various arrangements. We will touch on all four of them and explain the difference between rear-wheel, front-wheel, four-wheel and all-wheel drive.
Parts of a Drivetrain
The drivetrain requires several pieces working together in harmony to transfer power from the transmission to the wheels. This is the system that gets the car moving. Components include the driveshaft, differential, CV joints, U-joints and axle shafts. Let’s take an in-depth look at each of these.
Axle shafts – single rotating shaft. They are located on either side of the car’s differential.
Driveshaft – long steel tube that links between the transmission or transfer case and differential. It’s responsible for transferring mechanical power.
Differential – this is the one of the last stops before the power spins the wheels.
CV joints – otherwise stands for constant-velocity joints. They are designed to bend in any direction while turning the wheels at a constant velocity.
U-joints – stand for universal joints. This flexible pivot point transmits power to accommodate varying angles in the driveshaft.
Driveline, Drivetrain, Powertrain: What’s the Difference?
You will often hear technicians refer to the driveline, drivetrain and powertrain as if they were the same thing. For people that don’t understand the difference, this leads to lots of confusion.
The powertrain is simply everything that makes the car move. This includes your engine, transmission and all the parts that transfer the power from the engine to the wheels. The driveline consists of the components that connect the engine and transmission to your wheel axles. It does not include the engine or transmission. The drivetrain consists of everything from the engine to the wheels and is another way of saying powertrain.
Front-wheel drive vehicles otherwise referred to as FWD, signify that the power comes from the engine and turns the front wheels of a car. The rear wheels, in this setup, don’t receive any power of their own, but simply turn because the front wheels pull them.
Pros of a FWD Vehicle:
- Tend to get better fuel economy
- Maintains decent traction in snow since the engine is over the driving wheels
Cons of a FWD Vehicle:
- Aren’t as fun to drive; not used for performance
Rear-wheel drive, otherwise referred to as RWD simply means that the power goes to the rear wheels. This power then pushes the car forward. In this setup, the front wheels don’t receive any power, but instead, move because of the pushing force. This allows the front wheels to focus solely on maneuvering the vehicle.
Pros of a RWD Vehicle:
- Exceptional weight balance
- Exciting to drive; designed for use in most sports cars
Cons of a RWD Vehicle:
- Don’t perform well in poor weather
- Lack of traction on slick roads
Four-wheel drive vehicles, otherwise known as 4WD mean that power is delivered to all four wheels at the same time. When 4×4 isn’t engaged, you have the option to run in RWD to save fuel.
Pros of a 4WD Vehicle:
- Versatility for any terrain and weather condition
- Traction to go off-road
Cons of a 4WD Vehicle:
- Uses more fuel
- Typically heavier than other vehicles
With all-wheel drive, or AWD, the drivetrain employs front, rear and center differentials to provide power to all of the wheels. This means power goes to all four wheels at the same time. There’s no way to turn this off when using full-time AWD. In a part-time AWD or automatic AWD, the car operates mainly in two-wheel mode while power only goes to all the wheels when additional traction is required.
Pros of an AWD Vehicle:
Cons of an AWD Vehicle:
- Often uses more fuel
There are several aspects of maintenance you’ll want to consider when it comes to your drivetrain. Keeping these components in good working order saves you from costly repairs down the road.
The suggestions given below are simply guidelines. You will want to check with your service manual to find out the appropriate schedule for your vehicle. While it doesn’t hurt to service your car more than required, it is a waste of money.
Not only do you want to regularly check your fluid levels, but it’s critical that you change it often as well. Most manufacturers recommend a 15,000-mile fluid and filter change. If you regularly go off-road or drive under extreme conditions, you might need to do it more frequently.
Just like you would with your engine and transmission, you need to change the fluid in your transfer case. You will want to do this every time you change your transmission fluid (about every 25,000 to 30,000 miles)
Fluid changes should be performed to keep the internal components lubricated. It’s recommended to perform this service every 30,000 miles or so.
Check the boots on the CV-joints for rips, tears or dry rot.
Grease these regularly to keep the joints moving properly. Not all U-joints can be greased so you will have to check the kind on your vehicle.
It’s also wise to give your entire vehicle a check every few months. You want to look over the drivetrain and observe any spots that look excessively worn or damaged. Having these components repaired early helps you to stay on the road without incident.
Final Thoughts on Drivetrains
Now that you understand the types of drivetrains and how this term varies from the driveline or powertrain, it’s time for you to put some of your knowledge into action. When you go to buy a new or used car, you will now understand the basics of what you are looking at. In addition, you can service your car correctly and take control of its well-being. This vital aspect of your vehicle needs to be maintained and cared for if you want to spend less time in the repair shop.