Bad CV Axle Symptoms

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There are quite a few things that can go wrong with the constant velocity (CV) axle assembly. Leaking grease and normal wear can cause its parts to deteriorate. How will you know if your vehicle’s CV assembly is failing? Below is a list of bad CV axle symptoms and other important information on the assembly.

How to Tell if Your CV Axle is Bad

Here are some of the signs that may point to a bad CV axle shaft:

Clicking sound when turning

When the CV axle gets worn down due to constant use, it can loosen the joints. As the outer joints become unstable, they may produce a distinct sound that some people describe as a click or a pop. This sound is most noticeable when you make sharp or fast turns while driving around corners.

cv axle
The CV Axle transmits torque from the transaxle or differential to the wheels, enabling the vehicle to be driven forward.

You’ll hear the unusual clicking sound from the side of the vehicle with the faulty CV shaft.

Clunking sound when decelerating or accelerating

You may also hear unusual clunking or knocking sounds from the inner CV joint assembly when you decelerate or accelerate.

The sound may also come from an entirely different source, but hearing it should be a cause for concern.

Grease on the underside of the vehicle

The CV boot is what keeps the CV joints lubricated so they can function properly. It’s made of high-quality rubber that doesn’t rupture easily.

However, if the boot gets damaged, the grease inside it will fling onto the underside of the vehicle as the axle turns.

Vibration while driving

A damaged axle shaft or CV joint can affect the balance of the whole assembly as it rotates. When this happens, the shaft may vibrate excessively. These vibrations can intensify as you accelerate .

automotive cv axle
A clicking sound when turning can indicate a broken CV axle.

What Causes a CV Axle to Fail?

CV axles and joints may wear faster than normal if the CV boot is ruptured. When this happens, the joints lose grease and are no longer properly lubricated.

Moisture, water, and other road debris can also get inside the ruptured boot, making the CV joints vulnerable to faster wearing.

The joints will also fail prematurely if they’re put at an extreme angle because the vehicle’s suspension is modified. For example, a lifted truck may go through CV axles quickly.

In other instances, the CV joints may simply wear out over time.

How Long Can You Drive on a Bad CV Axle?

If one of the CV axle joints fails completely, you could lose control of your vehicle. This can lead to horrible accidents that may cost lives, so always be on the lookout for symptoms of a bad CV axle shaft and have your vehicle checked as soon as you detect red flags.

What is a CV Axle?

The CV axle (also called CV axle shaft and axle shaft) is responsible for transmitting torque from the transaxle or differential to the wheels, enabling the vehicle to be driven forward. There are two CV joints on its inner and outer ends that allow the CV axle shaft, which connects to the wheel hub, to transmit power without being affected by different road conditions. The joints are protected by a rubber boot filled with grease.

Together, the shaft, the joints, and the boot make up the CV axle assembly.

The CV axle is mainly used in front-wheel drive vehicles to transfer engine power to the two drive wheels.

Some late-model vehicles come equipped with independent rear suspension and many four-wheel and all-wheel vehicles also have CV axles. The CV axle improves the quality of the ride and the cornering ability of the vehicle with these suspension systems, especially on off-road terrain.

replacing CV axle
If one of the CV axle joints fails completely, you could lose control of your vehicle.

What Does a CV Axle Do?

A CV axle is a drivetrain component that transmits power from the transaxle or differential to the drive wheels at a variable angle and constant rotational speed without increasing friction. It facilitates a smooth transfer of engine power to the wheels without being affected by the turning angle of the wheel.

A CV axle extends from the vehicle’s transaxle or differential to one of the wheels. On both the inner and outer sides of the CV axle are joints. The axle shaft is able to transfer power at an angle thanks to the CV joints. These joints allow the axle shaft to move and adapt to different road conditions without affecting the transfer of power to the wheels.

Without the CV joints, the axles would break or bend whenever the vehicle drives over bumps or turns a corner. So it is important to inspect and maintain the CV joints properly because they keep the CV axle protected from strong impact forces.

CV joints need to be constantly lubricated in order to work efficiently, so they come with a rubber boot for each joint. This rubber boot is filled with grease that helps the moving parts work smoothly. The boot not only maintains lubrication for the joints, but it also protects the joints from moisture and debris.

If water or other road debris gets inside the CV joint, it won’t take long before the joint gets dislocated or worn down⁠. And when this happens, it won’t be long before you start noticing signs such as abnormal sounds and vibration, as mentioned earlier.

Together, the CV axle, the joints, and the boots work as a system that ensures an efficient and comfortable ride.

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In the Garage with is an online blog dedicated to bringing DIYers and devoted car enthusiasts up to date with topical automotive news and lifestyle content. Our writers live and breathe automotive, taking the guess work out of car repairs with how-to content that helps owners get back on the road and keep driving.

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