What Can Cause an Automatic Transmission Leak?

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An automatic transmission leak starts off being serious and gets even more serious down the road. Your vehicle’s transmission fluid protects the internal parts and gears just as the motor oil protects the engine. Low transmission fluid affects how the transmission shifts gears and can seriously damage the transmission in a short period of time. You might see red fluid in the center of your garage floor, and that is transmission fluid. CAR FIX lists the common causes of the leak below.

Drain Plug

The transmission’s drain plug does what its name suggests: it plugs the transmission, so fluid doesn’t leak out. As the plug wears down, it can eventually give a little, and your transmission pan will develop a small leak. The transmission can also leak if the plug is not tightened properly after servicing.


The transmission is located underneath your automobile, which makes life pretty hard for the pan. Road debris and rocks fly up and hit the pan all the time. If the debris or rock is big enough, it can pop a small or large hole in the pan. The transmission fluid stored inside will leak out of the hole.


Seals only last so long, and transmission and drivetrain seals are no exception. Your transmission has several seals that expand and contract between hot and cold temperatures. Over time, these seals can crack, including the pan and plug seals, the speedometer input seal, and the tail housing seal.

Pan Gasket

If your transmission’s pan gasket is the cause of your vehicle’s transmission leak, this is actually good news. The gasket is inexpensive and easy to replace, provided you haven’t been driving with low transmission fluid for a long time. Commonly, exposure to heat causes the gasket to fail.

Torque Converter

The torque converter pushes transmission fluid throughout the system. It’s basically a pump. The converter’s body can crack, and the needle bearings can get damaged as your automobile ages. If the torque converter is the cause of a transmission leak, there’s no fix; it must be replaced.

Fluid Line

Finally, transmission fluid lines are made from aluminum or steel, and you know both of these materials have limited life spans. They’re durable, but not forever. As with the transmission pan, these lines are subject to road-debris assault as you drive. Eventually, they will crack or fall off.

Get Your Automatic Transmission Leak Fixed Today

No worries! CAR FIX will find the source of your automobile’s transmission leak and fix it. Call our Oak Ridge, TN, shop, or schedule an appointment online today.

Photo by Jokic from Getty Images Signatue via Canva Pro

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