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

Last Updated on September 14, 2022 by John Robinson

Yes, you can! You will have to go through the driveshaft to get to it.

How much does it cost to replace the rear main seal?

How much does it cost to replace the rear main seal

A lot. Between $650 and $800.

The reason for this high-price is the amount of manpower and hours it takes to replace it. Most go through the transmission, and some even have to remove the engine to get to the seal. Each engine is, after all, different.

The part itself is quite cheap, $30-$50. So, if you repair cars yourself, and you have some knowledge, you can replace it.

How can I replace a rear main seal without removing the transmission?

replace a rear main seal without removing the transmission

If you have some knowledge of cars, understand your engine well, and you have the tools, then you can certainly replace your rear main seal yourself, and without removing the transmission.

Be forewarned, this type of procedure is usually done by professionals. If you’re uncertain, or you’ve never worked on a car before, it might be best to take it into an auto shop and let someone else do it for you.

So here is a brief rundown on how to replace a seal:

  • Raise the car with a jack – you will be working under the engine, so you’ll have to give yourself some space. Raise your car high enough to work comfortably.
  • Disconnect the battery – This is mostly for safety reasons. Disconnect the battery’s negative cable.
  • Remove the exhaust.
  • Take off the driveshaft and Flexi-plate – The driveshaft, also called the propeller, gives torque to your engine. The Flexi-plate is your final layer to remove. It’s a circular disc with holes in it.
  • Remove the Rear Main Seal Hood – the hood has around 6 main bolts that need to be unscrewed. These hoods are very fragile, so work carefully while removing them.
  • Remove the crankshaft seal – Usually when removing the hood, the seal itself should come off as well, but it doesn’t always happen. Carefully remove the seal and then install the new one.

Should I replace my rear main seal when replacing transmission?

Should I replace my rear main seal when replacing transmission

No. Unless the rear main seal is giving you problems or if it’s very old it should be left alone. These seals were built to outlast your engine. If replacing the transmission, you can certainly ask your mechanic to take a look at the rear main seal, but it’s usually not needed.

Is a Rear Main Seal Leak a problem?

Yes, yes and another yes. A rear main seal leak can do some serious damage to your car and it’s one of the most expensive repair jobs.

What makes a rear main seal leak so bad?

What makes a rear main seal leak so bad

In short, it runs a risk of pushing out copious amounts of oil and, in turn, damaging the engine.

A basic oil leak in your engine can cause your engine’s oil to dry up in weeks or months. It goes pretty slow.

A rear main seal can pump out your oil in a matter of minutes

Oil is the lifeblood of your engine, if it has no oil, it can’t keep itself lubricated and the engine will begin to grind against itself causing permanent wear and tear. If you suspect a rear main seal leak, rather get to an auto-shop immediately.

How do I know I have a Rear Main Seal Leak?

If you’ve got a rear main seal leak you will have oil dripping off either your engine oil pan or the front of your transmission called the bell housing. 

If you’re unsure, clean the engine thoroughly then run your engine and then check to see if the oil is leaking directly from the transmission bell housing. 

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John Robinson
John Robinson

Howdy! I’m John Robinson from Levittown, New York. I am a mechanical engineer for 15 years and already had an established car repair company. I developed a personal relationship with cars since I was a kid. I always love the sounds and smell emitted by a car or truck and even at construction machinery. Since then I have been married but my love for cars only grew.