How to Stop an Automatic Transmission Leak?

Automatic TransmissionHaving an automatic transmission in your car is a wonderful thing.  It makes traffic much less stressful and starting off on a hill much safer.  Automatic transmissions used to be unpredictable, clunky and make a car much less fuel efficient.  On the other hand, today’s automatic transmissions are getting increasingly more efficient and more predictable so having an automatic transmission installed in your new car is probably a no-brainer.

Automatic transmission, even newer models, all share some drawbacks.  When they fail, they tend to fail to the point where you can’t get your vehicle to move at all and are often left stranded.  The reason most transmissions fail and won’t let you move has a lot to do with the design of the valve body and how the transmission fluid is used to operate an automatic transmission.  Another problem with automatic transmissions is that new and old alike, it is very difficult to find a mechanic or shop who knows how to or is willing to diagnose a problem with your transmission or even do any work with it.  This is usually the case because electronic controlled transmissions require very specific computers to access their programs and are needed to perform most diagnostic work.  Also, old and new transmission alike usually require a significant amount of disassembly to determine what the fault is or where the problems are coming from.

This holds true for you as the owner of your car.  Realistically, the only thing you can do to monitor the health of your transmission is to regularly check the transmission fluid level and condition.  Most automatic transmissions have a dip stick to check the transmission fluid level at the back of your engine bay.  You should check the fluid level with the car idling on a flat surface after it has been driven to make sure the fluid is hot.  It’s often during these fluid level checks that you might notice a low transmission fluid level.  If you don’t catch a low fluid level during a regular fluid check, you will soon discover it when your transmission stops shifting correctly.

Low fluid levels in your transmission can only be for one reason.  A leak.  Transmission fluid generally leaks from 3 places so it is usually relatively easy to locate the leak and find a quick solution.

The most common leak location in an automatic transmission is from the transmission cooler lines.  Almost every vehicle with an automatic transmission has a transmission cooler to help regulate the temperature of the fluid in the transmission.  The cool sometimes is a separate heat exchanger, or sometimes it is integrated into the vehicle’s radiator.  Either way, it should be easy to locate the cooler lines as they should be the only hoses going into and out of the transmission.  If you discover a leak in the cooler line, usually at the end, simply replacing that line should stop your leak.

Another leak area is from a gasket in the transmission, like the gasket to the valve body if your transmission has an externally mounted valve body.  These gaskets can become dried or shrunken over time due to old transmission fluid or even normal wear and tear.  The last common leak area is the input or output seal in your transmission.

If you discover a leak from a gasket or seal in your transmission, the best way to stop the leak is to simply add BlueDevil Transmission Sealer to your transmission fluid.  BlueDevil Transmission Sealer can quickly seal a leaking seal or gasket stopping your automatic transmission leak and keeping your car working properly.

For more information about BlueDevil Transmission Sealer, click on the banner below!
BlueDevil Transmission Sealer





You can find BlueDevil Transmission Sealer at any of our partnering local auto parts stores like:

  • AutoZone
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  • Bumper to Bumper Auto Parts Specialists
  • S&E Quick Lube Distributor
  • DYK Automotive
  • Fisher Auto Parts stores
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  • Hovis Auto & Truck Supply stores
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  • Bumper to Bumper Auto Parts
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  • Consumer Auto Parts

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automatic_transmission.jpg – By ineb1599 – Licensed by Getty Images – Original Link

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10 responses to “How to Stop an Automatic Transmission Leak?

  1. I have a 2005 Ford Freestar, equiped with the AX4N auto transmission. These are notorious for differential seal leaks (where there was a leak). I lost approximately 2-4 ounces of ATF over 12k miles. I performed a ATF drop and fill along with your product and with in 200-300 miles no more pin drop pooling on the bottom of the transmission. Your products always seem to be superior to any other brand out there. Thank you for producing something that works.

    1. Luke-

      Yes, the BlueDevil Transmission Sealer is safe and compatible to use in your Ford powershift transmission. You will use one oz. of the product per quart of fluid in the system, and should expect to see results after approximately 100-200 miles of driving.

      Thank you!


    1. A Sibanda-

      Yes, the BlueDevil Transmission Sealer is safe and compatible to use on your Volkswagen Golf. You will begin by using one oz. of the product per quart of fluid in the system, and should expect to start seeing results after approximately 100-200 miles of driving.

      Thank you!


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