What is a CV Axle? | 5 Symptoms of a bad CV Axle

What is CV Axle?

A CV axle, also known as a constant velocity joint, drive axle, or half shaft, is a drive shaft that connects the front differential to each wheel. They are needed for transferring the torque from the transmission to the drive wheels at a constant speed while making sure that the suspension keeps moving in an up-and-down motion.

On all front-wheel drive vehicles, CV axle joints are located on both ends (inner and outer) of the drive shaft. However, they are also found on some rear-wheel or four-wheel drive vehicles, such as trucks.

cv axle

A CV axle design is such that it is attached with two clamps that hold it in place and is protected by a special grease and a plastic or rubber seal.

A CV joint will not require maintenance for a long time if the protection remains in place.

However, if the protective boot cracks or becomes damaged as a result of massive pressure on the driveline caused by shock landing, you will need to start looking for replacements.

Given their importance, faulty CV joints should be a source of concern for any vehicle driver. But, first, you need to be aware of the symptoms of a bad CV axle. 

Listed below are some of the common bad CV axle symptoms, and if you notice any of them, you must schedule a service appointment immediately.

Symptoms of bad CV Axle

The efficient working of the CV axle is very important for the efficient working of the vehicle. As the CV axle goes bad, it produces one of the below-given signs:

  1. Constant vibration while driving 
  2. Grease oozing out of the inside or the edges of tires
  3. knocking sound 
  4. Clicking noise on turns
  5. Bouncy ride

1) Constant vibration while driving 

If you have a worn or damaged CV joint, your vehicle will vibrate even on flat, even surfaces. This is because a bad CV joint will not be able to balance properly during rotation, and as you step on the gas pedal and accelerate, the vibrations will become more severe.

With increased speed, you risk losing control of the vehicle, putting you, your passengers, and other drivers on the road in danger.

You also risk the CV joint disintegrating while driving if it is not repaired or replaced promptly, which is obviously a potentially dangerous situation.

However, identifying this symptom can be difficult because numerous factors can cause vibration while driving.

2) Grease oozing out of the inside or the edges of tires

The CV axle joint is protected by boots that contain grease while the axle spins, preventing leaks. However, if this grease is thrown into the wheel or tire edges as the axle continues to turn, the resulting lack of lubrication may cause the CV joint to fail prematurely.

When you see grease along the edge of your tire, especially near a tear or tiny crack, it could be a sign of a bad CV joint. You can also turn the wheels at various angles and inspect the outer and inner boots for cracked or split rubber and/or grease.

Remember that replacing a torn boot is less expensive than replacing an axle, so inspect the boot regularly and check the inside edge of the tire for any grease leaks.

3) Knocking Sound 

When driving, a worn-out CV is known to make a distinct knocking sound. The source of the noise can be found in the inner or outer joints of a front-wheel-drive or rear-wheel drive vehicle, respectively. The sound could also be coming from the differential gears.

Put your vehicle in reverse and drive while rotating from decelerating to accelerating to determine if the knocking sound is caused by a faulty CV joint. If the noises become louder as you drive, it indicates that your CV joint is not functioning properly.

While the knocking noise does not always originate from the CV axle, you must remain vigilant and keep an ear out for it to become rhythmic.

4) Clicking Noise 

A damaged CV axle frequently makes a loud and distinct clicking sound as you turn the vehicle, and this sound will most likely become louder as you begin to move. The sound may be a loud click at times, or it may feel like a pop, and you will not forget it once you hear it.

To put this to the test, shift into reverse, turn the wheel to one side, and then step on the accelerator. As you move backward in a circle, the pooping or knocking noise will become louder. This is a clear indication that you have a faulty CV joint.

Once you’ve identified the symptom, you should take your vehicle to a service center right away. Depending on the severity of the joint’s condition, you may need to replace the entire shaft assembly in addition to the CV joint.

5) Bouncy Ride

If you’re driving down a paved road that’s flat and free of bumps and potholes, any vehicle that’s working normally should be completely stable. However, if your vehicle is bouncing around even on a flat paved road, it could be a sign of a bad CV joint.

As soon as you notice this problem, have a mechanic inspect your suspension components, including your CV joints, to determine the source of the problem. Don’t wait too long, or the situation will worsen, especially if you’re on a bumpy road, putting your safety at risk.

Replacement cost of CV Axle

The replacement cost of the CV axle varies according to the area where you live and the type of brand.

Early detection of a damaged CV joint boot can save you a lot of money. If you caught the problem in time, all you may need is a simple boot replacement and repacking of the CV joint with new grease. However, any delays might cost you more as you might have to replace the entire CV joint or drive shaft.

We strongly recommend using genuine CV axle parts provided by a manufacturer because they will be the strongest available, but you can obtain them from other channels at a lower cost.

In a repair shop, the replacement cost of the CV joint boot is between $180 and $350, and a driveshaft replacement can cost between $380 and $800. However, if you perform the service yourself, you can significantly reduce the replacement cost.

FAQ Section

What are the signs of bad CV Axle?

Following are the signs of a bad CV axle:

  1. Constant vibration while driving 
  2. Bouncy ride
  3. Grease oozing out of the inside or the edges of tires
  4. Clicking noise on turns
  5. Knocking sound 

What does it feel like when a CV joint goes bad?

You may see smoke coming from the broken joint and your front tires won’t point in the same direction since one will be completely disconnected from its drive axle. You may feel vibrations or a loud clunk sound when you accelerate, along with grinding or clicking noises when you turn.

Can I drive with a bad CV joint?

A severely worn out CV joint can even disintegrate while you’re driving and make the car undrivable. You may lose control of the vehicle entirely. It is not safe to drive with a damaged CV joint.

What does a bad axle sound like?

When constant velocity axles fail, you may also hear an unusual clicking sound may when turning the vehicle as joints become loose. These clicks are on the side of the faulty axle shaft and typically become noisier during sharp or fast turns.

What causes a CV joint to go bad?

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.

How long will a CV joint last once it starts making noise?

It might be safe to drive with a bad CV joint for a period of four to five months or a little bit more than that. When approaching six months, you should take your vehicle to a mechanic’s shop to get the faulty part replaced or repaired.

How long will a CV axle last?

CV joints last from 70,000 to 130,000 miles, and over, but technicians recommend that they be inspected periodically.

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