Can you hear a CV joint noise while you’re driving? If so, getting it fixed as soon as possible is crucial.
CV joint noises certainly sound irritating. That clicking or clunking sound might be getting on your nerves. However, it’s also doing some severe damage.
Understanding what’s causing a CV joint noise first requires knowing what they do. This guide will walk you through that, then explain what the noises are, how they might have been caused, and how to get them fixed.
In short, CV joint noise is usually caused by a lack of lubrication due to the grease escaping. In some cases, it could also stem from sudden, traumatic damage.
Let’s get started.
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What Is A CV Joint?
Before looking at the noises made by CV joints, here’s what they do.
A Constant Velocity (CV) joint is a connecting joint in a particular type of driven axle. These are known as driveshafts or CV axles.
Each CV axle has two CV joints: an outer and an inner. They’re each protected with a rubber boot and lubricated with a wretch-inducing amount of grease.
The outer CV joint (Rzeppa joint) connects to the wheel. The inner one (blog tripod) splines to the transmission differential.
CV joints allow the engine to send torque to the driven wheels while maintaining independent suspension. In other words, they preserve drive to the wheels while they steer or travel up and down independently from the vehicle body.
Note: a “driven” (or “live”) axle receives power from the engine and sends it to the wheels.
What Do CV Joints Do?
The transmission sits in the center of the car (for simplicity). One CV axle comes out of one side and attaches to the wheel. The other leaves from the other side, connecting to its respective wheel.
These two CV axles are collectively referred to as one axle on the car. You could refer to it as having two half-shafts.
The CV joints allow the driveshafts to send engine power to the wheels at a range of angles. Remember, in front-wheel-drive setups, these wheels need to move up and down with the road surface, as well as steer.
That means the axle’s angle must be constantly variable but always maintain speed coming from the engine and transmission. You might say it has to keep a “Constant Velocity” at all possible angles. Oh, look at that.
Note: consider what happens without CV joints. Imagine a rod connecting the two wheels directly. It would be spinning with torque from the transmission and engine. When you hit a pot-hole, the wheel in question drops down.
In turn, this pulls on the axle, causing the whole car to dip in that direction. Handling and maneuverability are drastically impacted, potentially leading to a crash. It also puts unnecessary force through the axle. CV joints allow independent suspension and thus prevent this from happening.
What CV Joints Are Made Of
The inner and outer CV joints are designed to allow for different types of movement.
Check out the video above. Please remember that it essentially shows an autopsy of a CV joint. Don’t start chopping your CV axle up if you want to use it again!
The outer CV joint is known as a Rzeppa joint, invented in 1926 by Alfred Rzeppa.
The housing contains ball bearings. These are placed between the outer bearing race and the housing. The inner bearing race sits inside the outer bearing race, and the CV axle splines into it.
The ball bearings sit firmly in their rotational positions. However, there’s plenty of room for them to move in and out. This allows the shaft output to rotate at the same speed as the input but in any available direction.
The inner CV joint (“blog tripod”) sits in a tripod housing. In it, you’ll find three rollers, each sitting on needle bearings. This allows for translational (“in and out”) movement and a small amount of shaft rotation.
Combined, the inner and outer CV joints transmit power to the wheels, accommodating both the suspension travel and steering.
What Cars Have CV Joints?
Cars have CV joints if the driven axle(s) has independent suspension. Your standard springs and struts are forms of independent suspension. 4x4s and some rear-wheel-drive vehicles are more likely to have solid axles.
These days, the vast majority of cars on the road have CV joints. You’ll find them in all modern front-wheel-drive vehicles and the front axles of 4x4s.
Rear-wheel-drive cars with independent suspension at the back will have CV joints, too.
You won’t ever find CV joints on non-driven (“dead”) axles. There’s no need for them since there’s no power to transmit to the wheels.
What CV Joint Sound Is Your Car Making?
When a CV joint wears, the most common thing you’ll hear is a clicking noise. You might also describe it as tapping or clunking. Popping noises can also come from damaged CV joints.
You’re most likely to hear it when turning either left or right or accelerating.
However, the CV axles transfer power from the transmission differential to the wheels. That means you could hear it any time you’re driving.
If the CV joints are making noise while going in a straight line at low speeds, there’s probably no grease left. Your car’s axle screaming is near total failure, so head straight to an auto shop.
Let’s assume that the noise you’re hearing is your CV joint. If you drive a car that’s:
- Front-wheel-drive, you’ll be hearing this sound from the front.
- Rear-wheel-drive, the noise will be coming from the back.
- Four-wheel-drive, the sound could be coming from the front (most likely) or the back.
Other Signs Of A Bad CV Joint
As well as the bad CV joint sound, watch out for the following signs:
- Grease around the rubber boot
- Grease dripping under the car
- Grease on the inside edge of the tire
- Strange vibrations coming from a corner of the car, particularly while accelerating around corners
- Pulling to one side under acceleration
How CV Joints Typically Break
If you hear noise from your CV axle, it’s wearing down and in the process of breaking.
In some instances, the joints might wear so much that something fractures and fully snaps. Watch out for these common occasions where CV joints often start to fail.
CV Boots And Clamps
The most common way CV joints wear is when the rubber boot tears or perishes or the clamps come loose. Without this protective boundary, grease leaks out, and dirt and debris make their way in.
It won’t take long before the joint becomes hot, seizes, cracks, wears, or otherwise breaks.
Shock Loading CV Joints
The other common way CV joints break is known as shock loading. This is when a driven wheel lifts off the road with power still being applied.
When the tire hits the road, it sends a sudden (and intense) force through the CV axle. As in anything, the joint is the weakest point, so it’s the most likely of all the components to give.
Shock loading is most likely if you drive off-road. For example, it could happen if you accelerate hard over a large rock or bounce up or down an incline.
Inappropriately complemented car modifications also put significant strain on CV axles.
Installing a lift kit means the angle the CV joints have to cope with is steeper than stock. As such, it’ll struggle more and is more likely to break when faced with shock loads.
The same principle applies to lowering kits, except now there will be less movement than the car was designed for. It puts a similar strain on the whole mechanism.
The same applies to larger and wider tires or heavier wheels. Your car needs to send more torque through the CV axles to rotate the wheel the same distance. In other words, you’re putting more strain on the CV joints than they were designed for.
What’s Making That Bad CV Joint Noise?
You may hear a clicking noise because the bearings inside are hitting the metal.
Usually, the CV joint is caked with mountains of grease. As with any moving component, this lubrication is vital for protecting it.
If the grease leaks out (and foreign bodies get in), there’s no longer anything to look after it. The metal starts hitting against bare metal, creating that click.
If grit and debris enter the CV joint, the bearings and casings begin to wear quickly. The foreign bodies physically impede how it functions.
Shock loading, as mentioned above, puts an instantaneous, immediate force through your CV axle. This could do damage pretty much anywhere if it’s powerful enough.
In some cases, you might hear a popping noise. This could be the bearings coming loose.
Can You Drive With A Broken CV Joint?
If you notice a broken CV joint sound coming from your car, go straight to a local mechanic.
Drive as slowly as possible. Doing so will prevent further damage and minimize the risk to yourself and other road users. If the car feels undrivable, you must pull over and call for breakdown assistance.
Don’t leave it. The longer you wait, the worse it’ll get.
If the joint fails completely, power won’t reach that wheel. All the torque will then go to the wheel on the other side, causing a serious imbalance. It could even start damaging the other one!
Basically, no – you can’t drive with a broken CV joint unless you’re heading off to get it repaired. For reference, the more severe the noise is, the worse the problem will be.
How To Fix A Bad CV Joint Noise
When it comes to fixing a CV joint, leave it to the professionals. This is a particularly fiddly baptism of fire if you don’t know your way around a car.
It’ll often need replacement rather than repair.
It’s wedged so tightly between the wheel hub and the transmission differential that just removing the shaft can take a long time. Expect bloody knuckles, bruised hands, and a whole lot of cursing.
How the CV joint will be fixed depends entirely on how bad the problem is and what’s causing it.
Grease Escaping From The Rubber Boot
When grease escapes from the rubber boot, it will lead to a bad CV joint sound.
If the problem’s only just started developing, there might still be plenty of grease inside. In this case, it’ll need a new rubber boot and the grease topping up, but that’s all.
The part itself won’t cost more than $20 in most cases. However, expect to pay for an hour’s labor, bringing the total to a little over $100.
Unfortunately, if it’s been going on for a bit longer, you’ll have run out of grease. The damage to the joint itself will be too significant. You’ll need an entirely new CV axle.
Any Other Kind Of Damage
If the CV joint gets damaged by shock loading or an inappropriate car modification, there’s nothing to be done. You’ll need a brand-new CV axle.
The mechanic should also check the related components: the transmission and wheel hub. Any physical damage to the CV joint may have led to harm to these parts of the drivetrain. They don’t usually need replacing, but it’s essential to check.
They might need to do some other work to prevent it from happening again. For example, you might want to return the suspension to its standard height if you’ve modified it. Alternatively, you might need a completely customized CV axle. That’ll be rather pricey.
How Much Does It Cost To Fix A CV Joint Noise?
As previously stated, a gumboot replacement should not exceed $100.
However, if you need a new CV axle, this will be more expensive. The part alone costs, on average, around $100 – maybe a little less. You’ll need to add on two or three hours of labor.
This will likely bring the total cost of a new CV axle to around $350 to $500.
Conclusion: Broken CV Joint Sounds And Why It’s Important To Fix As Soon As Possible
When you hear a clicking sound coming from your CV joint, get it fixed immediately. If you don’t, it’ll continue getting worse.
If left long enough, it’ll eventually become dangerous and much more expensive to repair.
Hearing a clicking sound when turning? Give your local mechanic a ring!