If you’re a motorist or car owner, you’ll face axle seal leak issues at one point in time. This crucial component keeps your car or truck running smoothly and prevents axle oil from leaking. Unfortunately, the axle seal does not last the lifespan of the car. They’ll eventually dry out or become brittle, causing oil leaks.
Whether you have a transmission axle seal leak or a rear differential axle seal leak, we’ll explain the possible causes, outline the most prevalent symptoms, and walk you through how to track and fix the oil leak. But first, let’s see what an axle seal does.
Axle seal explained
Car manufacturers use axle seals on several drivetrain applications. For example, cars, trucks, SUVs, sedans, and coupes have axle seals on their drivetrain. This seal performs two primary functions. The first function is to keep the transmission and axle oil where they should be.
Without this sealing function, there will be an axle seal leak on the transmission and the differentials. If this happens, the fluid leak will contaminate other components in the surrounding system, such as brake linings. It can also cause differential and transmission overheating due to low fluid levels.
The second function is preventing dirt and other contaminants from entering the diff and tranny. If foreign objects or contaminants get into the diff or tranny, it’ll cause accelerated wear or damage to planetary and other delicate gears in the system.
Axle seals come in different sizes and types depending on your vehicle type and location. But all of them serve the main purpose of preventing fluid leaks and keeping foreign objects out of the system. All vehicles, including front-, rear-, all-wheel-, and four-wheel-drive models, have axle seals.
All axle seals have round or circular shapes, a rigid circumference, and a hollow center. They are typically pressed and stationed in a place. And the axle is installed and spins through the hollow center. The hollow center of the axle seal is made of a flexible material that allows the axle to spin freely without oil spillage.
However, a few factors can cause a CV, differential, and axle shaft seal leak. We’ll explain this in detail, but before that, let’s look at some common axle seal symptoms so you can identify when the seal starts leaking.
Axle seal leak Symptoms
If you see red fluid leaking from a car and you suspect an axle seal leak, watch out for these symptoms.
Greasy spots around the seal
If a car, truck, or tractor axle seal leak occurs due to age, you’ll notice dampness around the axle seal. It may stay this way for a couple of months. But once it starts dripping, you risk incurring severe damage. However, the best time to replace a leaking axle seal is when you spot dampness around it. This is because there is no severe leak, and you don’t need to top up the fluid.
Oil puddles underneath your car
One common and earliest symptom of a front axle seal leak is oil puddles under the front of the vehicle. We explained earlier that the common function of the axle seal is to prevent oil leaks from the tranny and diff. If the rubber material becomes brittle, dries up, or cracks, it’ll allow oil to drip on the floor.
It’ll be more apparent when driving. When parked, the fluid drips slowly. So you’ll likely notice the leaks after parking for a few hours.
Reddish or strange fluid behind the tires
Another common symptom of a front and rear axle seal leak is reddish fluid under the tires. As pointed out above, a leaking axle seal drips slowly when the car is parked. Sometimes you won’t notice it until you turn on the engine and let it run. But as you drive, the leak becomes obvious, splashing behind the tires.
If you don’t track this on time, it may cause differential or transmission overheating or severe damage to the system. You can track this on your own. If you suspect any leak underneath your car, slide under the vehicle and inspect the tires, axles, and other components. You can also drive to a mechanic’s garage for a professional inspection.
Transmission overheating or slipping
A transmission axle seal leak will result in inadequate fluid in the system. If there’s an oil shortage, you’ll experience transmission slippage or overheating. If you ignore the leak and continue driving with it, it’ll eventually cause catastrophic damage to the gears and other delicate parts.
What causes an axle seal to leak?
The most prevalent causes of axle seal leaks are improper installation, loose bolts or fittings, dry axle seals, and damaged axles.
Dried or bristled seal
A dried or bristled axle seal will not perform its sealing functions very well. This will cause oil leaks when driving. It’ll also cause oil puddles on the driveway. However, the leak may not be noticeable when the vehicle is parked. If you suspect the axle seal is dry or bristling, park the vehicle on clean pavement and turn on the engine. You’ll see oil leaks from the seal as the engine runs.
Improper Installation
If you notice oil leaking from the axle seal after installing an axle shaft, you may not have installed the component properly. If you replaced the old axle, consider measuring it to ensure it is the same length and size as the new one.
Cracked or damaged seal
A cracked or damaged axle seal is another cause of an axle seal leak. The component can be damaged under normal use or if cracked. If the leak starts after removing and reinstalling the seal, it may have been cracked or damaged during removal.
Loose bolts or fittings
Another prominent cause is loose bolts or fittings. Depending on your vehicle design and the location of the seal, it may have a fitting and some bolts to hold it to the diff or tranny. If these fittings or bolts become loose, it’ll cause oil leaks.
But is an axle seal leak dangerous? Axle seal leak is dangerous because it can cause diff or tranny overheating, transmission slippage, and eventually cause catastrophic damages to the internal differential or transmission parts.
How to fix an axle seal leak
We have seen the common causes of bad axle seal leaks. Aside from improper axle or seal installation, your axle seal has likely achieved its sealing function for a long time. To fix axle seal leaks, you have to track the root cause and proffer a solution.
For instance, if the actual cause is loose bolts or a fitting, you have to remove the fitting, apply the recommended gum, and reinstall it. This time, ensure you tighten the fittings properly.
If the leak is caused by the wrong axle, remove the axle and get a larger one. And if it happens due to cracks or a broken seal, the only option is to replace it. You can do this yourself or have an experienced mechanic handle it. But, please, have an experienced auto mechanic do the job if you have a newer model car.
FAQs
Can I drive with a leaking axle seal?
It’s okay to drive with a small leak from an axle seal as long as you keep the differential or transmission fluid at the recommended level. The only issue you’ll have is just the messy or greasy diff or tranny.
However, do not drive the vehicle if you are leaking a lot. This is because you may not know when you run out of fluid. If the system runs out of oil, it may cause severe damage to the internal components.
How much does it cost to fix an axle seal leak?
Axle seal leak repair costs between $100 to several hundred dollars. A few factors, like your car make and model, mechanic, and region, determine the actual repair cost. In any case, it’s best to repair the axle seal leak once you notice it. This is true because the leak damaged the transmission, dropping an expensive repair bill on the table.
It is important to note that the front axle seal leak repair cost differs from the rear axle seal leak repair cost due to the cost of the seal and the labor required to replace them.
How serious is an axle seal leak?
An axle seal leak is a serious issue. While you can drive with a small leaking axle seal, do not drive with a large leak. Driving with a small axle seal leak is a risk, but you can drive with it as long as you keep the fluid at the right level. On the other hand, a large leak is a severe issue that can keep you stranded in the middle of nowhere.
How long can you drive on a leaking CV axle?
There’s no general duration you can drive with a leaking CV axle seal. How long you can drive with a leaking CV axle depends on the severity of the leak. For instance, a bristled axle seal that has not yet started leaking oil even while driving on the highway will last for several months. This type of leak only leaves the seal area greasy.
However, large leaks (depending on their severity) can last from a few hours to a few months, as long as you maintain adequate oil levels.
How long does it take to fix a leaking axle?
This depends on the mechanic doing the replacement and your vehicle type. If you have a certified mechanic fix the leak, expect to spend 1 to 2 hours. But if you decide to fix the leak yourself, it’ll probably take 3 hours or more. Kindly note that this is only for fixing a single axle seal leak. Therefore, if you want a mechanic to replace four axle seals, he’ll spend around 6 to 8 hours.
How many axle seals does a car have?
Every vehicle has axles that transfer power to the wheels. These axles have different designs and numbers of internal components. Most axles have two to three seals on a wheel. This means that cars usually have 8 to 12 axle seals that prevent the tranny and differential fluid from leaking.
What happens if you don’t fix a wheel seal?
If you continue driving with a leaking wheel seal, the grease on the wheel bearings will leak. If these bearings do not have enough grease, they will freeze up and prevent the wheel from moving as it should. At first, the wheel will start making noise on the highway. But as the issue intensifies, the wheel bearings will fail, preventing the wheels from turning.
What is the difference between an axle seal and a wheel seal?
The axle seal prevents differential and transmission fluid from leaking. It also prevents foreign contaminants from getting into the system. On the other hand, a wheel seal prevents grease on the wheel hub from leaking out.
Both of them play an essential role in preventing leakage. The only difference is where they are installed and what leakage they are preventing.
Final Words
Do not ignore axle seal leaks because they can cause severe damage to the transmission or differential if the system runs out of oil. Aside from the embarrassing oil puddles under your car, it can cause transmission slippage, overheating, accelerated wear on the internal gears, and serious damage to other internal components.
If you notice any of the above signs of axle seal leak on a Honda Accord or your respective car model, drive to a mechanic to have them track the leading cause and rectify it. A certified service technician should identify the root cause and proffer solutions or recommendations.
