A car’s powertrain includes everything involved in making a vehicle move – including the engine. A subpart of the powertrain is another collection of components that is referred to as the drivetrain system. The role of the drivetrain is to move the wheels of your car by coupling together many mechanical parts such as the driveshaft, wheels, and axle to efficiently use the power supplied by the engine. The car’s transmission is a major part of the drivetrain and the entire system is physically linked – running from rear to front and spanning both passenger and driver’s side of the vehicle.
Parts of the Drivetrain
- Transmission – Uses gears to transfer engine power to the driveshaft and wheels and change the vehicle’s drive-wheel speed and torque in relation to the speed and rotational power being generated by the engine
- Driveshaft – A long tube of steel linking the car’s transmission to the wheels, effectively transferring mechanical power from the transmission to other drivetrain components.
- U-joint – Universal joint provide a flexible pivot point that allows for the many angles the driveshaft will need to maneuver while under power.
- CV Joints – Constant velocity joints are mounted on the driveshaft, allowing the wheels to continue to drive at a constant velocity while flexing and turning in any direction.
- Differential – Right before the wheels start spinning, the wheels differential not only drives the pair of wheels, it also allows the wheels to rotate at different speeds.
- Axles – Single shafts that rotate on either side of the differential and transfers power from the drivetrain assembly to the drive wheels.
Front Wheel Drive vs Rear Wheel Drive
You may have never seriously thought about it, but when you choose to buy a front wheel, rear wheel, or 4 wheel drive (4WD), you are choosing the type of drivetrain arrangement the car will have. The most commonly purchased vehicles have historically been the rear wheel drive vehicle. In these cars, the engine power is transferred to the rear tires and technically provides superior braking, and better handling and steering.
When the front wheels are powering the movement of the car, the drive shaft that typically runs the length of the car is eliminated. This puts most of the drivetrain components in the front of the vehicle and results a lighter weight car and an engine that is mounted sideways – running horizontally and not vertically. Front wheel drive cars tend to accelerate better and have more traction on ice, sand, snow, and gravel. Also, when the front wheels are used to pull a car, fishtailing around curves or corners is drastically reduced.
Your car’s drivetrain is a mechanical system that should last throughout the life of the vehicle. Typically, your car will show obvious symptoms while driving to indicate that your drivetrain needs attention, such as difficulty turning corners, rough driving and wheel vibrations, or loud noises especially from the rear of the car.