Modern cars have so many fancy features that it’s hard to keep track. But at the end of the day, not as much has changed from the first motor vehicle until today. They both still use wheels, an engine block and two sets of car axel. Without these axles, you’re not going anywhere fast.

All four or more wheel motor vehicles use either axles or tracks. So, unless you’re driving a tank, your car has axles, and they need maintenance because they play a critical role in the operation of the vehicle. If you don’t, they’ll often become the main culprit of any car troubles that you experience, especially if you hear vibrations or loud clunking sounds.

In this guide, we’ll look at what a car axel is and how you can identify if any issues are arising from it. Most likely, they will become harmed on older vehicles due to a lack of maintenance. However, after crashes or impacts, you’ll often find that a car axel can become misaligned, bent out of shape or broken, leading to a dangerous driving experience.

If you think that you’re having car axle problems, you should stop driving and have a mechanic look underneath. Most often, a skilled technician will be able to tell in a few seconds whether or not there is a problem. Due to the simplicity of an axle, it usually requires little if any testing and you can diagnose problems easily. Although fixing them is much more challenging.

What Is A Car Axle?

An axle is a central shaft which connects the two wheels. An axle can either be fixed or not, whereby it either rotates with the wheels or allows the wheels to rotate around it while staying stationary itself. Due to its place, whereby it connects the chassis to the driving components, the axle will also support the vast majority of the weight of the car. It will:

  • Support the car weight
  • Drive the wheels
  • Provide protection
  • Connect the drivetrain to the wheels

It’s also common for the axles to turn, passing this torque and adjustment to the wheels, allowing the vehicle itself to take a different angle. To put it simply, the car axle is the middle point for all torque and drive. The power doesn’t go straight to the tires; it must first go through the axle which also absorbs the weight of the vehicle.

Two Types Of Axle

While there are a wide variety of axle, the two most common are drive and dead axles. The first is due to the driveshaft which is a rod that goes upwards into the transmission and connects with the engine. Thereby, the engine powers through the axle, which will spin and twist the wheels, causing momentum and acceleration forwards in the car.

The opposite is the dead axle which isn’t in connection to the driveshaft or engine. Rather than being driven, it only moves because of the forward momentum of the vehicle which turns the wheels and therefore the dead axle which is attached. The only reason for the dead axle is to help to support the weight of the car more evenly across the entire chassis.

On most cars, there is one of each. An F​WD will have the dead axle on the rear and the drive axle on the front, hence the phrase front wheel drive. On the flip side, rear wheel drive cars have the drive axle at the back, and four-wheel drive vehicles use two drive axles rather than only one. By doing so, they can generate more torque for getting out of sticky situations.

Due to the rotation of the axle, it’s often necessary for there to be bearings and grease which help to prevent rubbing and ensure smooth rotation. Bearings are particularly necessary on the dead axle because it’s because driven, rather than doing the driving.

Car Axle Problems And Symptoms

A huge range of car problems is a symptom of an issue with the axle. Due to the role they play in forward movement as well as weight distribution, any small issue can be magnified and cause serious problems which can lead to dangerous situations and accidents. If you think your axle could be the cause, take the vehicle into a trusted mechanic as soon as possible.

While all of these problems could be due to something other than a damaged or broken axle, most likely this is the cause. Axles are relatively easily damaged, given how strong and thick they are. The reason for this is because they experience a lot of movement and are on the undercarriage where rocks or obstacles can damage them.

If you ever get into an accident and begin to notice these symptoms, you must see a mechanic. Often collisions can cause a misalignment of the axle with the wheel which if left alone can cause breakage and more serious car trouble. Within a minute a specialist will be able to tell you if there is a problem with the axle and give you options to remedy the situation.

Severe Vibrations

Often you’ll find that your car is experiencing severe vibrations. These will be most noticeable on rougher terrain or uneven roads, but you should still notice them on the flattest and most perfect paving. The cause of this is typically a misalignment of the axle with the wheels, causing an improper transfer of forces, hence the shaking which reverberates up the chassis.

Depending on the severity of the issue it might be possible for a specialist to tighten the bearings and do a realignment. But if the shaking and vibrations are due to a crack or break in the axle, then you might be forced to replace the entire thing. It’s impossible to know the solution without taking a look at the undercarriage.

Fortunately, vibrations can be due to minor issues and in the grand scheme of things, aren’t the biggest deal. If the axle breaks, you usually won’t be able to move, especially if it’s the drive rather than the dead axle. Vibrations can be caused by something as minor as a loose bearing or nut, causing shaking of the drivetrain.

One way to test if it’s the axle is to find an empty parking lot and gently accelerate. If the shaking is worse when accelerating but reduces at the same speed when gliding, most likely there is an issue with the connection between the axle and the drivetrain. However, if it continues then the problem might be in at the juncture of the wheel and the shaft, which can be problematic.

If you’ve experienced vibrations or shuddering before, you should know the difference between minor and significant shakes. If the entire vehicle is rattling, pull over and call a mechanic. It’s not safe to drive in this condition. If it’s only minor, you might consider driving to the nearest dealership or mechanic who will be able to take a look for you.

Shaking and rattling might coincide with clunking and clanking, but the two issues don’t necessarily have to be related. It’s possible that they could ensue from separate breakages. However, if they both start at the same time, it’s very likely that you have a serious problem that needs immediate attention before you can continue to drive the vehicle.

Another issue that can cause these same symptoms is a misalignment of all of the different tires on the car. If this is the problem, you’ll probably notice the vibrations as you get near to 50 miles per hour and then they will subside after 70. As you speed up, the differences become less noticeable, and therefore the vibrations tend to reduce.

On the other hand, you might only notice shaking and vibrations when you hit the brakes and start to slow down or come to a stop. This symptom almost guarantees that the issue lies with the breaks and not the axle itself. It will become particularly bad as you brake harder and you might feel the vibrations in the steering wheel or the pedal.

The cause of this is typically an out of round brake pad, whereby it doesn’t sit perfectly onto the tire and jumps. This vibration causes rapid acceleration and deceleration, repeatedly at quick intervals. As a result, it feels like vibration and can reverberate up the pedal and through the entire chassis. Changing brake pads or tires will fix this typically.

If you find that the vibrations continue to get worse as you speed up, you should stop and the car and pull over. You might notice a burning, unpleasant odor. This scent is a sign that a brake caliper is stuck. If there is no smell, it’s probably an axle which is damaged or heavily misaligned. You should call an emergency mechanic at the roadside.

Clunking And Clanking

Clinking can be due to a wide variety of issues, which is why it’s important to take note of the timing of the noise. Depending on when you experience the sensation it might be one of a variety of problems. Typically, axles will cause clunking when the gears shift or as you accelerate. You’ll notice it over the drive axle.

If you notice that when you put the car into gear, there is clunking, or as you swap gears, then your vehicle is indicating that it can’t get enough drive from the transmission. Typically, this is caused by an issue at the junction of the drivetrain and the axle joint. Although, the problem could also lay with the transmission itself.

Due to the complexity of this issue, you’ll likely need to speak to a very experienced mechanic who will be able to diagnose the issue. They might put your vehicle onto a dyno which will spin the tires and look for issues in the transmission and gearbox. Alternatively, a visual examination can quickly identify cracks in the joints of the axle which might cause the clunking.

If you turn down the radio and pay attention, you might be able to identify specifically where the noise is originating. Most likely it’s coming from the drive axle, but it could also be in the dead axle if there is a crack or break. If you are particularly vigilant, you might know if it’s also on the left or the right.

Alternatively, there might be a particular motion or situation when the issue occurs. It’s often the case that taking a turn will cause the noise, which is indicative of a CV joint wearing down, cracked or misaligned. This joint is there is transfer power from the axle to the wheels, causing the forward motion.

But the CV joint also ensures that the wheels turn when you twist the wheel, hence why this problem often becomes notable when you’re going around a corner. Replacing a CV joint isn’t overly expensive, at least compared to the majority of problems which are related to the axle, which often demand a full replacement.

Leaking Grease

Another, although far less common, the problem is leaking grease. Unfortunately, it’s very hard to notice this issue if you’re not actively looking for it. Therefore, we would always recommend that you inspect your vehicle regularly to look for minute differences like this which can save you a fortune down the line.

Grease is necessary to facilitate a smooth movement and to prevent scraping which can cause serious damage to the axle and even cause it to crack or snap. If you notice leaking grease under your car or along the inner side of the tire, most likely it’s coming from a leaking axle boot or CV boot.

This boot is the rubber covering which goes over the CV joint between the wheel and the axle bar. A leaking of grease doesn’t mean the axle itself is broke; it indicates a problem with the rubber covering. However, if not taken care of, the axle joint won’t be lubricated, and this will guarantee issues down the road.

Therefore, it’s vital that you visit a mechanic and have the rubber replaced to ensure that it has a tight seal. They might also need to change your oil to make sure that the joint has lubrication before you take it back out onto the road. Another issue with the broken seal is that dirt can enter into the joint, causing friction and eroding the metal much faster.

No Movement

Finally, the most noticeable problem that might occur due to the axle is a failure to move at all. This issue happens when the drive axle is mangled or broken. It might be due to a full crack in the bar, preventing it from passing drive to the wheels, or because of a failure for the drivetrain to move the axle, preventing movement.

If your car isn’t moving, it’s going to take a fraction of a second for a mechanic to diagnose the problem. Typically, it’s an incredibly obvious break which will need repairing. It’s very rare that you can fix the axle, it must be replaced to prevent any weak spots which would only crack again in the future when placed under a large amount of stress.

Unfortunately, if your car isn’t able to move due to an axle problem, the repair is going to be very expensive. It’s not uncommon for cars to become ‘totaled’ due to an axle breakage or a drivetrain error because the cost of replacing it is incredibly high, especially due to the labor fee. Keep this in mind when you’re heading to the dealership or garage to examine the vehicle.

You can diagnose this problem easily at home. Start the engine and put the car into gear. If you press the gas and you hear the engine rev but don’t have any movement at all, there is a problem with the universal joint. If you have slight movement, you might have a transmission issue or a broken drivetrain connection.

On the flip side, if you don’t hear revving or the engine sounds weird or quiet, most likely the problem isn’t originating in the axle. It’s more likely in this case that the transmission, gears or engine block are damaged and aren’t transferring any power down through the drivetrain. In this case, turn off the car and have a mechanic come to pick up your car and take a look.

Maintaining Your Axles

Replacing and fixing problems with your axles is incredibly expensive. Therefore, you would be wise to do everything within your power to prevent damage before it occurs. One of the easiest ways to do this is to drive safely and avoid accidents. Even minor collisions can cause axle damage, particularly if the crash comes from the side or at an angle.

Likewise, you should be regularly examining your car to look for problems. Checking for oil leakages takes a few seconds and is the leading cause of CV joint problems. Take your finger and rub it alongside the inner part of the tire to feel for oil or grease. Alternatively, you can use a flashlight to check if the seal on the rubber is still intact.

If you do notice any issues, no matter how small, it’s best to contact a mechanic sooner rather than later. Waiting while you hear rattling or feel vibrations will let the problem get worse, causing more serious damage which can be very expensive to repair. Nip the issue in the bud early by repairing small problems rather than replacing the entire car axel.

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