Why Is There Transmission Fluid Leaking From the Bellhousing?

<Transmission Fluid Leak, transmission fluid leaking from the bellhousingTransmission fluid leaking from the bellhousing of your transmission means you’ve got a leak somewhere on the front of your transmission.  Unfortunately there area few places the fluid could be coming from and they are all pretty difficult to inspect.

The first step in diagnosing any transmission fluid leak from the front of your transmission is to see if your transmission has an inspection cover.  Most bellhousings do not go all the way around. They are sometimes split in half where the engine block meets the oil pan or have a cover at the bottom or top where you can remove a small plate and peek inside the bell housing.  Worst case scenario, you should at least be able to remove the start to get a peek at the flywheel.

Inspecting the flywheel, flex plate, clutch plate or torque converter is the best way to tell where your transmission fluid leak from the bellhousing is actually coming from.

Where is your transmission fluid leaking from the bellhousing coming from?

  • The torque converter
  • The transmission fluid pump seal
  • Transmission cooler lines
  • Bearing retainer plate
  • It’s not transmission fluid?!?

Once you’ve popped the inspection cover off look at the flexplate or flywheel.  If it’s got fluid dripping off the transmission side then you’ve got a transmission fluid pump seal leak if you’ve got an automatic transmission or a transmission front seal leak.  If there is no fluid on the flexplate or flywheel then you’ve got a bearing retainer plate leak in a manual transmission or a transmission cooler leak on an automatic transmission.

In an automatic transmission if the whole torque converter is covered in fluid, then chances are your torque converter has sprung a leak.  In any of these cases if the hard part repair doesn’t make sense for your vehicle or your budget, consider using BlueDevil Transmission Sealer to stop your leak guaranteed!

But what if your leak isn’t actually a transmission fluid leak?  Manual transmission fluid looks a lot like engine oil or clutch fluid.  If you’ve got a manual transmission check for a rear main seal leak or a leak in your clutch slave cylinder before you start looking for transmission leaks.

You can pick up BlueDevil Transmission Sealer at one of your local auto parts stores like:

  • AutoZone
  • Advance Auto Parts
  • CarQuest Auto Parts
  • NAPA Auto Parts
  • O’Reilly Auto Parts
  • Pep Boys
  • Canadian Tire
  • Walmart

20 responses to “Why Is There Transmission Fluid Leaking From the Bellhousing?

    1. Alfreemon-

      Thank you for asking about your Mercedes Benz E320. The BlueDevil Oil Stop Leak would be to seal the kind of leak you’ve described. You will add one oz. of the product per quart of fluid in the system, and should expect to start seeing results after 100-200 miles of driving.

      Thank you!


  1. Thank you for the article. 2008 62te leak showing at the inspection plate. Seems to leak cold or hot. Just had the pans off for a while. Working around my injury. Got put back together and now this leak.

    1. Larry,

      Thanks for your question about your transmission leak. Usually, leaks from the inspection plate come from the front seal in your transmission. These leaks happen most often either from age or from the vehicle sitting for a long time. You can try BlueDevil Transmission Sealer or you can remove your transmission to get a look at that seal behind the torque converter to see if it is indeed leaking and to replace it.

      Thanks again for your question!
      -BD Auto Pro

  2. I have a 01 lexus gs300 v6.2jz trans. I pulled tranny and replaced the torque converter refurbished. I replaced the front seal.i flushed the system new filter and pan gasket. And it’s a steady stream of trans fluid with vehicle started and in drive. Its killing me cause I’ve had several different inputs on it. Thanks in advance.

    1. Mike-

      Based on your description, this could be an issue where one of the seals isn’t on tight enough or even perhaps a loose hose connection. If you are able to pinpoint the location of the leak, you should be able to go from there. If not, you may want to bring the vehicle to a transmission specialist for inspection.

      Thank you!


    1. Jason-

      The BlueDevil Transmission Sealer is intended to treat leaks coming from rubber seals/gaskets. If the leak is coming from one of those rubbers, you would be a good candidate for the product.

      Thank you!


  3. Hey my nissan quest 07 was sitting for about two years before I got it I just bought it 2 weeks ago we had to replace the alternator and when we change it from gear to gear it knocks depending on the way we are sitting we where on the road going up a hill the other day and my brother was tryna change from low to drive to help the shift from knocking so bad and it shut off we put it in park and crank we got to the store and its was leaking badly like a consistant line of transmission fluid can you please tell me what that could be and what choices do I have to fix it

    1. Dalton-

      Thank you for asking about your Nissan Quest. More than likely, the knocking noise you were hearing would be attributed to the system being too low on transmission fluid. Based on your description, with the vehicle sitting for that long, the rubber seals/gaskets may have shrunken or become brittle from not getting the proper lubrication. They may have deteriorated to the point where the only way to fix the issue would be to have said seals/gaskets replaced. Your best bet may be to bring the vehicle to a transmission specialist for inspection.

      Thank you!


  4. My car started leaking fluid after a drive on the highway it was smoking from the rear, it didn’t run hot but it’s leaking pretty bad now, and wasn’t leaking before will devil help?

    1. Marco-

      BlueDevil Transmission Sealer will treat leaks that are seeping or lightly dripping. As long as you are not losing fluid too quickly, you would be a good candidate for the product. You should expect to start seeing results after 100-200 miles of driving.

      Thank you!


  5. My 2001 Nissan Pathfinder Le is leaking bad from the front of the bellhouing . Can bluedevil fix this problem? I don’t know where the leak is but it’s coming from the front of the transmission.

    1. Melvin-

      Thank you for asking about your Nissan Pathfinder. BlueDevil Transmission Sealer is intended for leaks that are seeping or lightly dripping. Based on your description, you may be losing fluid a little too quickly for the product to be successful. A hard part repair may be your best option.

      Thank you!


  6. Hi, I just bought a Volvo V40 D2 Powershift and it turns out the previous owner overfilled the transmission with 9L of oil instead of 6L. This has caused the bell housing seal where it connects to the engine to leak. My mechanic doesn’t know whether that was from all the pressure of adding so much oil or whether it is because something has failed internally within the clutch mechanism. Do you guys think it was just from pressure as the car runs and drives perfectly fine and the leak was only a small drip. We haven’t checked if it leaks after removing all the old excess fluid and replacing it with the correct amount. However my mechanic says that if the seal has gone bad then it’s going to cost £2000 to repair.

    1. Muntasir-

      Thank you for asking about your Volvo V40. If the transmission was overfilled by 3 Liters, that more than likely would be the cause of any internal damage the system has developed. Too much fluid would cause hard shifting and excessive wear on the gears when shifting, eventually causing you to hear grinding gears when shifting. Continue to monitor the fluid level and check for leaks. If you are experiencing any hard shifts or starting to hear a grind noise, we recommend bringing the vehicle back to a transmission specialist.

      Thank you!


  7. I have a 2006 GMC Sierra Denali crew cab AWD 2 days ago I’m driving on ramp at 40mph then I throttle down to accelerate to merge ahead of traffic about 6miles I noticed smoke and pulled off the off ramp saw transmission fluid got towed to the house check out the bell house put transmission fluid back in only three quarts with out starting truck no leak
    Started the truck no until transmission fluid get hot but it’s not on the flywheel but off the torque converter slinging off the converter so is going to be a seal problem or a converter replacement

    1. Ryu-

      Thank you for asking about your GMC Sierra. Based on your description, it sounds like your assessment is right in that the issue is more than likely related to a blown seal or torque converter. Unfortunately, it sounds like you may be losing fluid a little too quickly for the BlueDevil Transmission Sealer to be effective. We recommend bringing the vehicle to a transmission specialist for a possible replacement seal.

      Thank you!


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