Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. What Can Cause a Car to Leak Transmission Fluid?

What Can Cause a Car to Leak Transmission Fluid?

transmission fluid leak

A vehicle’s transmission fluid system is closed, which means that the fluid or oil inside can’t escape when things are working properly. Therefore, when vehicles leak transmission fluid, it indicates another problem than just a need to add more fluid or oil. If your transmission leaks, however, don’t automatically assume the worst. There is a wide variety of causes for a leaking transmission, ranging from simple fixes to fairly serious issues. That doesn’t mean you should put off having your vehicle inspected. Even delaying easy repairs can lead to greater problems when ignored, which will ultimately cause a bigger headache and blow to your pocketbook later. Here are the most common causes of a transmission fluid leak:

  • Loose pan: The transmission oil or fluid pan is designed to catch extra fluid that would otherwise escape, so – if the pan is loose – there is nothing to prevent transmission leaks. The pan may simply not have been bolted back correctly after changing the filter or come loose while driving over rough terrain.

  • Oil pan gasket: High temperatures or faulty manufacturing can lead to a cracked or otherwise damaged oil pan gasket. Although this part is inexpensive to replace, more serious problems can ensue if the issue is left unattended.

  • Misaligned drain plug: After a transmission fluid flush or other transmission service, the drain plug may not have been screwed back in properly along the threads. This can lead to a leaking transmission but is relatively easy to set aright.

  • Damaged bell housing: When driving on gravel roads or on other challenging surfaces, it is possible for a rock or other item to strike the bell housing with such force that it becomes cracked or develops a hole where transmission fluid can escape.

  • Punctured or cracked fluid lines: Similarly, items picked up from the road and flung by the tires can strike the transmission fluid lines and cause transmission leaks.

  • Faulty torque converter: Less commonly, the torque converter, which is responsible for switching gears in automatic transmissions, may be damaged and allow transmission leaks. Unfortunately, this is a costly repair that is also difficult to diagnose.

Unless you are checking your car or truck’s fluid levels as part of general maintenance or notice your gears aren’t shifting as usual, you may not even know your vehicle’s transmission leaks. Another sign that there is a transmission oil leak is the accumulation of a red, slick liquid beneath your car, which may be the size of a small coin or much larger, depending on the severity of the transmission fluid leak. If you know your fluid is low or have seen evidence of a leak in a parking lot or driveway, call us for a consultation with one of our experienced mechanics. He or she can help diagnose the cause of your leaking transmission and make appropriate recommendations for repairs.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


More related articles

Veteran and Military Driver Laws and Benefits in Idaho
The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP)...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...

Related questions

Q: Automatic to Standard conversion

Hello, thank you for writing in. A swap like this can be complicated if you are not used to doing it yourself. This is something you may want to seek help with. The vehicle with the manual transmission has all...

Q: Q: Car jerks when i put it gear

Assuming your car has an automatic transmission, it sounds like you may be low on transmission fluid. Automatic transmissions use transmission fluid that is pressurized to shift gears. When the transmission is low on fluid, this can cause delays in...

Q: Q: Car makes grinding noise

Have an experienced technician with an automotive stethoscope inspect the vehicle. Some noises can be difficult to diagnose and the stethoscope will lead the tech to the root of the problem. The cooling fan can break and make noise as...