A separate part on a metal surface.Though it is not technically part of the transmission system, the rear main engine seal is a component we often have to replace for customers at Ralph’s Transmission. If this critical seal is damaged or weakened, oil leakage can cause serious powertrain problems that could affect both the transmission and the engine itself.

What is the Rear Main Engine Seal?

The rear main engine seal connects the engine’s crankshaft to the transmission. As the engine runs, the crankshaft turns and provides power to the transmission. The transmission then distributes this power to each of the four wheels. Therefore, it’s important that the seal is healthy and doing its job to prevent leaks in this sensitive part of the powertrain system. When we perform transmission rebuilds at Ralph’s Transmission, it’s common for the rear main engine seal to get replaced at the same time. We usually find that they are worn and it’s a convenient time to install a new one when the transmission is out of the vehicle.

Signs of Rear Main Engine Seal Failure

There are some common signs you can look for to let you know when you have a problem with your rear main engine seal:

  1. Major Oil Leak—If you notice a puddle of oil under your vehicle and/or you constantly have to refill your oil pan, it’s never a good sign. Leaks can occur in multiple places throughout the engine’s assembly. A significant oil leak closer to the middle of the vehicle is often related to the rear main engine seal. One closer to the front of the vehicle may be something else leaking under the hood.
  2. Oil Saturation—Smaller leaks may not leave big obvious puddles of oil. If you are able to look under your vehicle and see that there is a significant amount of crusted oil coating the transmission bell housing or the back of the engine, it might be a sign that the rear engine seal is getting weak.
  3. Check Oil Light—Your vehicle’s “check oil” light may come on to let you know that it is low on oil or some other problem is occurring. It could be the rear main engine seal leaking or something else worth getting looked at by a mechanic.
  4. Check Engine Light—Your vehicle’s “check engine” light is generally a catch-all warning that can come on for any number of automotive issues. A failing rear main engine seal could be the culprit.

If you notice any of these common rear main engine seal failure symptoms or experience any transmission issues, call the Central Valley drivetrain experts at Ralph’s Transmission at 209.526.1909. It’s best to deal with any minor problem before it develops into something much worse. You can also schedule your service appointment online.

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