The CV axle is mainly used in front-wheel drive vehicles to transfer power from the engine to the two drive wheels. In this post we are going to explain everything about the common failures of a CV axis, Tripoid or constant velocity axis.
Some late model vehicles come equipped with independent rear suspension and many cars also have CV axles. It is good that you know the signs and symptoms of a bad CV axis.
What is the CV axis or constant velocity axis?
The CV axle (also called constant velocity axle or homokinetic joint) is responsible for transmitting engine torque from the transaxle or differential to the wheels, allowing the vehicle to move forward.
There are two CV joints at its inner and outer ends that allow the CV axle, which connects to the wheel hub, to transmit power without being affected by different road conditions. The joints are protected by a rubber sheath filled with grease.
Together, the axle, joints, and boot make up the CV axle assembly . These components work together as a system that ensures efficient and comfortable driving. Without CV joints, the axles would break or bend every time the vehicle hit potholes or turned a curve. Therefore, it is important to properly inspect and maintain CV joints because they keep the CV axle protected from strong impact forces.
How to know if the CV or tripoid axis of my car is bad?
CV shafts and joints can wear faster than normal if the CV boot breaks. When this happens, the joints lose grease and are no longer properly lubricated.
Moisture, water, and other road debris can also get into the broken boot, making CV joints vulnerable to more rapid wear.
Joints will also fail prematurely if they are set at an extreme angle because the vehicle’s suspension is modified. For example, a lifted truck can wear out CV axles quickly.
In other cases, the CV joints can simply wear out over time.
Common Failures of a CV Axis, Tripod , or Constant Velocity Axis
There are quite a few things that can go wrong with the constant velocity (CV) shaft assembly. Grease leaks and normal wear and tear can cause your parts to deteriorate. How can you tell if your vehicle’s CV assembly is failing? Below you will find the signs and common failures of a CV axis:
1- Clicks when turning
When the CV axle wears down from constant use, it can loosen the joints. As the outer joints become unstable, they can produce a distinctive sound that some people describe as a click or pop.
This sound is most noticeable when making sharp or fast turns when driving around curves. You will hear the unusual clicking noise from the side of the vehicle with the faulty CV axle.
2- Metallic sound when decelerating or accelerating
You may also hear unusual rattling or knocking noises from the inboard CV joint assembly when you slow down or accelerate.
The sound can also come from a totally different source, but hearing it should be cause for concern.
3- Grease on the underside of the vehicle
The CV joint boot is what keeps the CV joints lubricated so they can function properly. It is made of high quality rubber that does not break easily.
However, if the boot is damaged, the grease inside it can fall on the underbody of the vehicle when the axle turns.
4- Vibration while driving
This is one of the common CV axis failures that you can spot quickly. A damaged CV joint can affect the balance of the entire assembly when turning. When this occurs, the shaft can vibrate excessively. These vibrations can intensify when accelerating.
What to do in case of having a damaged CV axis?
You can lose control of your vehicle if your CV joints are worn. This can potentially lead to accidents and personal injury. For this reason, worn constant velocity joints must be replaced immediately .
If you notice any of the symptoms mentioned above, it would be best to immediately inspect your CV joints. Once you’ve confirmed that the problem is caused by worn CV joints, you’ll need to get a replacement. Aftermarket CV axle assemblies range from $26 to $9,000, while aftermarket CV joints run from $60 to $800.
If you plan to do the repairs yourself, you may need specific equipment, such as a durable torque wrench/breaker bar and an appropriate electrical outlet. As for repair instructions, it’s best to consult a repair manual or vehicle-specific database. However, if you don’t have a lot of repair experience, you can have a certified mechanic do the work for you.