How to Replace Rear Main Seal Chevy 350

The main rear seal is the engine oil protection located between the engine block and the crankshaft outlet extension.

Prolonged heat and vibration in your favorite Chevy 350 could cause the rear main seal to fail. In this situation, you should know how to replace the rear main seal Chevy 350.

In this article, we will guide you step by step on how to make this possible.

We will also teach you how to replace a rear main seal without removing the transmission, to make the process as easy as possible for you.

How to Replace Rear Main Seal Chevy 350: Easy Steps

Step 1: Disconnect the battery

The first thing you need to do when replacing the Chevy 350’s rear main seal is to disconnect the battery.

In fact, whenever you think about how to replace a rear main seal without removing the transmission, for safety reasons, you should remove the battery if or when you need to. Carefully disconnect the negative and positive terminals.

Also remove the battery from your car, for your safety. This will keep the process free of unwanted accidents.

We all know that the process is complicated. If you want to take your car to the mechanic, no problem.

But why spend money on something you can do yourself and learn in the process?

Step 2: Remove the driveshaft

No matter if your car is a front or rear wheel, it is important and vital to remove the driveshaft in the event of replacing the main seal and to allow more clearance.

Therefore, remove the driveshaft carefully. Once the driveshaft is removed, continue with the next step.

Step 3: Remove the flex plate

Now we are going to eliminate the Flex Place, for this process, we will assist with a screwdriver to remove the flexible plate and a wrench.

With the help of the wrench and the screwdriver, you must break the loop of the flexible plate. After removing it, you can see the back main seal.

Now carefully unscrew the seal with the help of your tools from the back.

Step 4: Rear Main Seal Cover Removal

Now that you’ve removed all the extra parts, it’s time to remove the rear main seal. It’s time to put all your energy into removing the main seal.

The process of replacing the Chevy 350 rear main seal is almost complete. Generally, the rear main seal is pressed into the hood through bolts in the engine block.

Before entering the engine block, proceed to the rear main seal. So, before you get to the rear main seal, you will need to face the rear main seal hood.

Now, in the process of running the engine, the crankshaft comes into action. In the center of the crankshaft is a small part, which is a pilot carrier.

The main seal cover usually includes pins about 6-10 mm that must be removed. Once those bolts are removed, remove the seal cover.

At this point, you must take extreme care in removing the seal housing, as it is constructed of very delicate aluminum materials that are prone to cracks and dents. Use caution and remove it carefully.

Step 5: Remove the crankshaft seal

Sometimes the seal comes out with the hood but if it doesn’t, you have to do it yourself. Different cars and models have different object locations.

In these cases, you must understand that there is a strong possibility that the seal has become stuck inside the crankshaft.

To remove it, just push the crankshaft. This will help you remove the seal.

This seal is the main rear seal that needs to be removed. Remove it and you are ready to install a new one.

Here’s remove the rear main seal Chevy 350 without removing the engine at any time.

Why is replacing the rear main seal so expensive?

There are several factors that make the steps on how to change the rear seal on the transmission expensive when taking it to a professional, let’s see.

The complexity of the work

Replacing the rear main seal requires some knowledge, engine construction, and how it connects/disconnects to the transmission.

There are several ways to replace the main rear seal, and because of that, depending on which techniques the shops use, you will be charged accordingly.

Therefore you will always see different costs in different workshops. Apart from that, you will also see the quality of the professionals who operate in the shop.

Special tools

Special tools such as transmission jacks, if they need the engine raised; a wide range of torque wrenches, safety equipment, engine support bars, among a lot of other special tools that only help greatly to make the process easier and more practical for operators.

Mechanical parts

This does not present a serious problem at cost, but can easily be added to the bill. This can be a change of seals or gaskets, nuts, etc.


How much does it cost to fix an oil pan gasket leak?

The cost is between $100 and $400, but, it will all depend on the type of part to be replaced, etc.

For parts, you might pay around $50 and $150+ to replace the oil pan gasket.

As you may notice, the parts themselves are not very expensive, but the labor can often be labor-intensive.

Can you drive with a leaking oil pan gasket?

Driving with an oil leak will usually cause additional problems to your vehicle, such as engine damage for example.

If you have an oil leak, it is best not to waste time and take your vehicle to your nearest mechanic.

How serious is an oil pan gasket leak?

Engine oil is used to keep the engine warm and maintain friction and together with the coolant.

If the oil pan leaks, the oil level will drop and this will cause the engine to overheat, resulting in malfunction.

Wrap Up

Changing the rear main seal on a Chevy 350 or any other car is easy, but you know it’s not easy, so we could learn how to replace the Chevy 350 rear main seal.

The process is not easy, if you think something is wrong or you are not quite sure what you are doing, do not hesitate to call an expert.

They will assist you in any situation and give you some very good advice on the way.

Liam Dare

As CEO of, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.