What is an Axle Seal Leak? | How to fix Axle Seal Leak?

The function of the axle seal is to connect the axle to the gearbox and prevent transmission oil leakage. While a minor leak from the axle seal may not have an immediate impact, it can lead to further problems if ignored, limiting the vehicle’s driveability. This article describes the axle seal causes, symptoms, and how to fix it.

What is an Axle Seal?

An axle seal is a major part of your vehicle’s axle system that is installed to keep the lubricating fluid inside the axle and prevent it from leaking out.

Axle seals are usually located on the outer end of the axle shaft and are mounted in an axle tube or housing. The main function of these seals is to prevent oil from leaking out onto the brake assemblies, wheels, and other components of the axle system.

Axle seals are very important to ensure the efficient performance of the vehicle’s axle system. A damaged or leaky axle seal may cause lubrication loss. The excessive loss of lubrication may cause excessive wear on the axle and other components, as well as decreased engine performance.

Signs of an axle seal leak may include oil leaks around the wheel or axle, grinding or whining noises from the axle, or a noticeable decrease in the vehicle’s performance and fuel efficiency.

Causes of a Leaking Axle Seal

• Poor quality seals: Using low-quality seals can increase the likelihood of a leak.
• Overheating: Excessive heat can cause the axle seal to melt or sustain damage, resulting in oil leakage.
• Incorrect installation: Poor installation or damage during axle seal installation can also cause leaks.
• Corrosion: Corrosion can lead to damage of the axle seal in several ways. The buildup of rust or other corrosive substances on the axle can cause abrasion or pitting, which can compromise the integrity of the seal. Corrosion can also cause the seal to become misaligned or to lose its proper fit, leading to leaks.
• Wear and tear: As time passes, the axle seal may experience wear and tear, leading to oil leakage. When the seal deteriorates, it fails to prevent oil from seeping out of the axle. Poor vehicle maintenance or rough driving can also contribute to this problem.
• Excessive pressure: Excessive pressure on the seal can cause it to malfunction and result in an axle seal leak.
• Accidents: An accident can also cause damage to the rear axle seal. A hard impact can break the seal and lead to oil leakage. It is crucial to have the vehicle inspected after an accident, even if no visible damage is apparent, to prevent future issues with the axle seal.

Symptoms of Axle Seal Leak

Following are the symptoms of the rear axle seal leak:

1) Oil Puddles Under Your Car

The oil puddle on the driveway is one of the clear symptoms of the axle seal leak. This is typically one of the initial signs of a problem with the seal.

As the seal deteriorates, it develops cracks and tears, allowing oil to seep out and collect under the vehicle. The oil stains will be more apparent after the car has been parked for a while, as the fluid has had time to drip and accumulate on the ground.

2) Dampness Around the Seal

Initially, a minor axle seal leak may only result in a damp area around the seal. However, as the problem worsens, it becomes more likely that fluid will start to leak onto the ground.

The leaked fluid can also come into contact with the exhaust system, producing a burning odor when the exhaust is hot. Moreover, the leak can contaminate the brake shoes, which can lead to unusual noises and affect the vehicle’s braking performance.

3) Clicking Noise

A leaking axle seal can also cause a clicking noise. When the differential gears are not properly lubricated due to the seal leak, they can produce a clicking sound as they make contact with each other.

4) Low Oil Level

The low oil level is one of the most common symptoms of an axle seal leak. If the axle seal is leaking, it will cause a loss of oil, which can result in low oil levels in the differential or transmission.

Read More: Low Engine Oil Symptoms and Causes

5) Strange Fluid Behind the Wheel

Another symptom of an axle seal leak is the presence of reddish-brown fluid drops behind the left front wheel, where the driveshaft connects to the transmission. This symptom may be more noticeable during highway driving, as the fluid leakage tends to increase at higher speeds.

If this issue is left unchecked, the transmission fluid level may drop, resulting in transmission slippage and even permanent damage. Although it can be challenging to check the issue by getting under the car, a mechanic can identify the problem when the car is lifted up or highlighted in the repair pictures they provide.

6) Burning Smell

A burning smell can be produced when leaking oil from a damaged axle seal comes into contact with hot engine components.

7) Excessive Vibration

When an axle seal is worn out or damaged, it can lead to vibrations that are noticeable in the steering wheel or the floor of the vehicle.

8) Poor Efficiency

A leaking seal can cause the differential to work less efficiently, leading to decreased performance and fuel economy.

How To Replace an Axle Seal?

1. Jack up the vehicle: Life the front of your car by using a jack and support it with a jack stand.
2. Remove the wheel: Remove the wheel from the axle that requires a new seal by using a lug wrench.
3. Locate the axle seal: Find the rear axle seal, which is typically installed on the differential near the back of your vehicle.
4. Remove the axle: Depending on the vehicle, you may need to remove the brake caliper, rotor, and axle nut to extract the axle from the differential.
5. Take out the old seal: Remove the old seal from the differential casing by using a seal puller or pry bar.
6. Clean the area: Remove the oil or debris from the differential housing by using a clean cloth.
7. Install the new seal: Apply some clean oil to the new seal and place it into the differential housing. Use a seal driver tool or a large socket that fits over the seal to gently tap it in place, ensuring it’s flush with the housing for a proper seal.
8. Reinstall the axle: Gently reinstall the axle into the differential and tighten it with the axle nut. You should also reinstall the brake caliper and rotor if needed.
9. Install the wheel: It’s time to secure the lug nuts according to the manufacturer’s instructions.
10. Lower the vehicle: Gently remove the jack stands from underneath your car.
11. Check the oil level: After installing the new axle seal, inspect the differential oil level and add more if needed.

How much does it cost to repair an axle seal leak?

The fixing or repairing cost of an axle seal leak depends on the vehicle model and labor cost. The average replacement cost of the axle shaft seal is from $230 to $310. In this cost, the estimated labor costs are from $190 to $270, while parts are priced at $40.

FAQ Section

What is the function of the axle seals?

Axle seals are essential components that prevent the leakage of transmission oil or differential oil by sealing the connection between the CV axle (driveshaft) and the vehicle’s transmission or rear axle differential.

Can I drive with a leaking Axle Seal?

The extent of fluid loss due to a leaking axle seal can impact the operational dependability of the vehicle. If the fluid loss is significant and affects the transmission, it is not recommended to drive the vehicle. However, if the leak is minor and a temporary fix is required, topping up the transmission oil can help. It’s important to avoid overfilling as this can lead to permanent damage to the transmission, resulting in a costly replacement.

How many are rear axle seals present in a car?

Typically, a car has a pair of rear axle seals positioned on either side of the differential. These seals serve the purpose of preventing oil leakage from the differential and keeping debris and dirt from entering the gears.

What is the average lifespan of a rear axle seal?

The lifespan of a rear axle seal typically lasts around 30,000 miles, but this can differ based on the vehicle’s make, model, and driving habits. Consistent maintenance of the rear axle seals may assist in prolonging their lifespan.

Can a leaking axle seal affect transmission?

The front axle seal is designed to prevent oil leaks from the differential case or axle tube. Its location can vary depending on the vehicle’s design. A damaged front axle shaft seal can result in leaks of differential oil, which can damage the transmission.

Where is the axle seal located?

The placement of the axle seal can differ based on the specific model of the vehicle. In cars equipped with semi-floating drive axles, the seal is typically situated on the outer edge of the axle tube. Meanwhile, for trucks or SUVs that have a front CV axle, the seal is found at the inboard end of the axle, where it connects to the differential.

Is an axle seal leak dangerous?

An axle seal leak may not be immediately dangerous, but it can lead to more serious problems if left unaddressed. A leaking axle seal can cause oil to leak out of the differential, which can cause the differential to run dry and overheat. Overheating can cause serious damage to the differential, which can be expensive to repair or replace. A leaking axle seal can also allow dirt and debris to enter the differential, which can cause damage to the gears and bearings.

Can a bad axle cause shaking?

A faulty axle can result in suspension vibration that can be quite pronounced. The shaking usually intensifies at higher speeds, and it’s crucial to address any axle problems as soon as possible. Worn constant velocity (CV) joints can also cause vibration issues.