CV Half Shaft Assembly
A CV half shaft assembly is an essential part of your vehicle’s drivetrain. Also known as a constant velocity (CV) axle, it transfers power from your transmission system to one of the drive wheels. The latter means you have a CV half shaft assembly on every side of the vehicle. Each of your CV axles is able to move up and down, and side to side, while constantly rotating, which makes it possible to turn your front wheels and accommodate different road conditions in motion.
Every CV half shaft assembly consists of an inner and outer CV joint connected to each other with a shaft. The inner CV joint is attached to the transmission, while the outer one mounts into a drive wheel. Both of the joints feature a rubber boot to protect them from dirt, dust and contaminants, and to prevent special grease used for their lubrication from splattering in different directions.
In many cases, a CV half shaft assembly can last the life of a car, although it may eventually fail just like any other part in a vehicle. But the good news is that you’ll notice several warning signs of a bad CV axle prior to its failure, so you’ll have some time to fix the problem before it makes your vehicle undriveable.
Signs of a bad CV half shaft assembly
Clicking sound when turning
If you notice a clicking sound when you turn left or right, most likely, your outer CV joint is about to fail. The sound should be especially noticeable at low speeds, coming from the joint that is opposite of a turn.
Clicking sound during acceleration
This warning sign is an indicator of a failing inner shaft. You can check the condition of your inner CV joints by pushing down or releasing your gas pedal very quickly. If you hear a clicking sound, in most cases, one of your inner CV joints is failing. But keep in mind that this can also be a sign of a bad transaxle, U-joint or differential, so your CV joints should be properly inspected before you replace them.
Excessive vibration when driving can be caused by a worn-out or damaged shaft. If it is the root of the problem, the vibration should increase when you accelerate.
Grease on the inner side of a wheel
If a boot that protects a CV joint gets cracked or broken, the grease inside the boot can leak out, staining the inner part of a wheel along with steering and suspension components. This bad boot should be replaced as soon as possible to prevent damage to the CV joint.
CV half shaft assembly replacement
Unless another is provided in your owner’s manual, a CV half shaft assembly doesn’t require routine maintenance. However, it is a good idea to inspect your drivetrain once or twice a year.
Properly operating CV half shaft assemblies are crucial for a safe driving experience. If you notice any sign of a bad axle, don’t risk your neck driving the vehicle. A faulty CV axle can not only make your driving unsafe but also cause damage to your transmission and drive wheels.
Call your mechanic or have your vehicle towed to a repair shop once a bad CV axle is detected. The mechanic will inspect both CV half shaft assemblies for excessive play and damage. In some cases, you’ll just need to replace a broken boot, leaving everything else as it is. If one of your CV joints is faulty, you can replace it or the entire assembly with a new part. As a rule, the other CV half shaft assembly doesn’t need to be replaced if it is in proper condition.
The labor and repair bill may vary depending on the cost of replacement parts, the amount of labor involved and the design of your vehicle. In most cases the repair procedure will involve disassembling several suspension and steering parts. That’s why it makes sense to check the condition of these components and replace them if necessary.
Both CV half shaft assembly inspection and repair should be done by a professional as this job requires specific tools and a thorough knowledge of the drivetrain.