Rear Main Seal Leak Repair Cost and Symptoms

Rear main seal leaks is a familiar problem for some cars and can cause a lot of damage if left unnoticed.

If you move your car on the driveway and see a small puddle of oil, it is a sign that you have an oil leak, possibly a rear main seal leak to repair. Rear main seal leaks need to be fixed as soon as possible as the leaking oil is essential for the engine to lubricate all necessary parts properly, and the leaking oil is dangerous for the environment.

This article will cover the rear main seal leak repair cost, considering parts and labor, and the symptoms you should look out for.

What Is the Rear Main Seal?

The rear main seal is a gasket and is one of the most critical components connecting the engine and transmission. The rear main seal gasket protects the transmission and engine connection from leaks.

The rear main seal gasket is located at the rear of the engine, where the engine connects to the transmission. You can find the rear main seal facing one of the two wheel arches on sideways mounted engines.

The rear main seal gasket is made out of synthetic rubber, and it is just as strong as any other gasket on the car.

It’s durable and made to last a long time, but the rear main seal gasket can fail due to several reasons mentioned further down in this article.

You need to disconnect the engine from the transmission, and you may even need to remove the engine to reach the rear main seal to repair it. If the rear main seal is not fixed, your car may lose a lot of essential engine oil.

What are the Symptoms of a Rear Main Seal Leak?

If you suspect that your rear main seal is leaking, there are several symptoms you can look for.

One of the most common symptoms is an increase in oil consumption. You may also notice an increase in engine noise, or a burning smell coming from the engine.

If your car is leaking oil, it’s important to have it repaired as soon as possible to prevent further damage. Here’s three common symptoms of a rear main seal leak.

1. Leaking Oil

Oil consumption and forming of oil puddles underneath the vehicle can signal early-stage failure of the rear main seal.

However, with how expensive the rear main seal is to replace, you should rule out everything else before making a conclusion.

Sometimes when a car starts to use a lot of oil or there are oil puddles on the ground under the car, it means that the rear main seal is starting to fail.

But before you decide to replace the seal, you should check to make sure that it’s not something else that’s causing these problems.

Rear main seals can be expensive to replace, so it’s worth checking everything else first.

There are many possible reasons for an oil leak, and some are more likely than others. The valve cover gasket, intake manifold gasket, and distributor gasket should all be checked to see if they are the problem.

If you find oil dripping on the top of the bell housing, one of these gaskets is likely leaking, rather than the rear main seal gasket.

Another probability is a leak at the rear of the oil pan gasket. This leak is often confused with a rear main seal leak, so it should be inspected thoroughly to rule it out.

One common issue that can cause oil leaks is a leaky differential. The differential is the part of the car that helps distribute the power from the engine evenly between the left and right wheels.

If the differential starts to leak, it can cause the oil to drip close to the tires. This can create oil puddles on the ground.

If the rear main seal is leaking, the puddle should be centered with the car, and the transmission bell housing, where the transmission and the engine connect, should be wet with oil.

Although the bell housing might be wet, make sure the leak is not above the transmission dripping down, making the transmission bell housing wet.

2. Smell of Burning Oil

A car leaking oil on hot engine parts is a potential fire hazard, and the burning oil smell a lot.

It might be hard to tell where the weird smell come from and if there’s something wrong, but if you lift the hood of your car, you will be able to smell the hot oil.

3. Illuminated Engine Oil Light

When the engine oil light comes on, you should stop your car and turn off the engine as soon as possible.

You don’t know if there is a tiny oil leak or a huge one, so it’s vital to stop the car as soon as possible.

If you see any leaks or spills, try to find out where they are coming from. If you can’t, it’s best to call a tow truck and take it to a mechanic, as the rear main seal gasket might have failed.

Ignoring the warning light could lead to expensive repairs down the road.

Rear Main Seal Leak Repair Cost

The rear main seal leak repair cost will depend on the make and model of your vehicle, and the garage or mechanic carrying out the work. Generally, however, the rear main seal leak gasket is about $100, and the labor cost ranges from $500 to $1800, averaging at $1100.

Replacing a leaking rear main seal gasket is a time-consuming job that can take up to 6 to 10 hours, even for a professional mechanic.

As mechanics usually don’t trust the customer’s diagnostics, you will also have to pay for a troubleshoot as the mechanic want to verify that your diagnosis is correct.

Suppose the mechanic verifies that the rear main seal is leaking the transmission need to be separated from the engine without anything taking damage. On some makes and models, the engine has to be removed.

The transmissions flywheel or flexplate, depending on if your car has a manual or automatic transmission, needs to be removed to access the seal housing, need to be removed.

Every part removed to access the leaking rear main seal must be carefully handled and cleaned. You also have to do many tests afterward to see if the repair was successful.

Plus, they need to invest in professional tools to work on the rear main seal.

Considering all the time-consuming steps, it’s no wonder the cheap leaking rear main seal gasket is expensive to replace.


Is a Rear Main Seal Leak Serious?

Rear main seal leaks are dangerous and can cause a lot of damage to your car as a significant leak could occur quickly. If your vehicle has a rear main seal leak, you should take your vehicle to a mechanic as soon as possible.

Can You Replace a Rear Main Seal Without Removing the Transmission?

Yes, replacing a rear main seal without removing the transmission on some makes and models is possible. The procedure may be a little more complicated, but it can be done. First, you will need to remove the driveshaft and then the oil pan, and you will be able to visually see the rear main seal and replace it as needed.

Is It OK to Drive With a Rear Main Seal Leak?

You need to replace the rear main seal gasket if it’s leaking as it can cause expensive problems to your car. Also, the oil leaking on the ground causes an environmental issue. There is also a fire hazard because the oil spills on hot engine parts can catch fire.


If you are experiencing any of the rear main seal leak symptoms, it is important to bring your car in for repair as soon as possible.

The sooner you get the repair done, the less expensive it will be.

There are many potential causes of an oil leak, so it’s important to rule out everything else before deciding that the rear main seal is the problem.

The rear main seal replacement is costly due to the number of hours it takes to replace the rear main seal as the transmission need to be separated from the engine.

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Robin Söder

Robin has always been passionate about cars ever since young age. Over the years, Robin has worked on thousands of cars and gained invaluable experience in the process. He is considered an expert in his field and is often consulted by other mechanics for advice.

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