The drivetrain isn’t a single piece connecting to the axles. It’s actually a series of parts that include the driveshaft, differential, axle shafts, U-joints and CV joints. Here’s a quick breakdown on what each part is and what it does.
This is a long steel tube that connects to your car, van, SUV or truck’s transmission at one and, and the other end is connected to your vehicle’s wheels. When the transmission is on, the driveshaft transfers torque from the engine to your wheels.
The differential allows your wheels to spin at different speeds, which is required to keep your car, truck, SUV or van from losing grip on the road. These speed differentials are also required to keep your vehicle from pushing your wheels too hard into the tarmac, which would strain your car and can lead to wear and tear significantly faster than it would otherwise.
There are multiple types of axle rods, or shafts, that are responsible for rotating your car’s wheels while supporting the weight of your vehicle. They’re usually found in the front, rear, and “stub” of your car. Here’s a quick breakdown.
This type of axle rotates with your car’s wheels and comes in two pieces, known as half shafts. These pieces are connected by the differential and are responsible for providing power from the engine to the driving wheels.
This axle is usually made from carbon or nickel steel so it can be extremely sturdy. There are four main parts to this axle, which are the beam, swivel pin, track rod and stub axle. Together, the pieces help steer and absorb shock from driving on an uneven road.
These are attached to the front axle with kingpins on on end and they’re attached to the front wheels on the other end. These are also called stud axles and they allow your car to make angular movements when you’re steering.
These universal joints, also called U-Joints, are actually small pieces that connect driveshafts to differentials. It’s shaped like a cross with bearings at each end to it can move laterally or side-to-side of the driveshaft. These joints can connect the driveshaft to the transmission and also connects two driveshafts to each other in some vehicles.
Your car’s constant velocity joints, or CV joints, attach to both ends of your drive shafts, meaning there are a set of inner CV joints and a set of outer CV joints. The inner CV joints connect to the drive shafts and transmission, and the outer joints connect drive shafts to the wheels. These joints are required to help transfer torque from the transmission to the drive wheels, as well as assist with your car’s suspension. To keep CV joints healthy, they’re packed with grease and sealed tightly with a plastic or rubber boot. These can last for over 300,000 miles if the boot isn’t damaged.