What can cause a car's transmission fluid to leak?

The car's transmission fluid system is sealed off, which means that the fluid or oil inside can't come out when everything is working properly. So when cars leak transmission fluid, it indicates a different problem and not just...

The car's transmission fluid system is sealed off, which means that the fluid or oil inside can't come out when everything is working properly. Therefore, when vehicles leak transmission fluid, it indicates a different problem, and not just the need to add more fluid or oil. However, if your transfer is leaking, don't automatically assume the worst. There are many reasons for a transmission leak, from simple fixes to fairly serious problems. This does not mean that you should put off getting your car checked out. Even delaying simple repairs can lead to big problems if ignored, which will end up causing a big headache and hitting your wallet later. Here are the most common causes of a transmission fluid leak:

• Free pan: The transmission oil or fluid sump is designed to trap excess fluid that might otherwise leak out, so if the sump is not secured there is nothing to stop leaks from the transmission. The sump could simply be bolted on incorrectly after changing the filter, or unscrewed while driving over rough terrain.

• Oil pan gasket: High temperatures or manufacturing defects can cause cracking or other damage to the oil pan gasket. While this part is inexpensive to replace, if the problem is left unattended, more serious problems can occur.

• Wrong drain plug: After flushing the transmission fluid or doing other transmission maintenance, the drain plug may not have been properly tightened along the threads. This can cause the transmission to leak, but this is relatively easy to fix.

• Bell body damaged: When driving on gravel roads or other difficult surfaces, a stone or other object may hit the bell body with such force that it cracks or creates a hole through which transmission fluid can leak.

• Pierced or cracked fluid lines: Likewise, objects lifted off the road and thrown off the tires can hit the transmission fluid lines and cause the transmission to leak.

• Faulty torque converter: Less commonly, the torque converter, which is responsible for shifting gears in automatic transmissions, can be damaged, leading to transmission leaks. Unfortunately, this is an expensive repair that is also difficult to diagnose.

If you don't check the fluid level in your car or truck as part of general maintenance, or notice that your gears aren't shifting normally, you may not even know your vehicle's transmission is leaking. Another sign of a transmission oil leak is a buildup of red, slippery fluid under the vehicle, which can be the size of a small coin or much larger, depending on the severity of the transmission fluid leak. If you know you have a low fluid level, or have seen signs of a leak in your 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 transmission leak and provide appropriate repair advice.