5 Common Causes of Leaking Transmission Fluid

A transmission is responsible for intelligently directing power from the engine to the wheels, so it's one of your vehicle's most important systems. To run effectively, your transmission requires a healthy flow of clean transmission fluid. When there isn't enough present, serious internal damage can occur and everyday performance can suffer.

Low transmission fluid is often caused by a leak. If this occurs when the vehicle is parked, you may notice a bright red fluid with a noticeably sweet smell pooling beneath it, but fluid can also leak while you drive and go undetected.

Here are just five common causes of leaking transmission fluid.

1. Worn Seals or Gaskets

Your transmission system includes many seals and gaskets that are responsible for preventing leaks. Just a few include the transmission pan gasket, rear main engine seal, and front input seal. Unfortunately, seals can become worn and start to fail. This may happen due to issues such as rubber deterioration or poor alignment, and a transmission fluid leak will generally be the result.

2. Bent Transmission Pan

Your transmission fluid is housed in the transmission pan. While pans often last the life of a vehicle, they can be bent relatively easily when too much force is applied during servicing. The transmission pan will no longer be able to create a tight seal when this happens, which means transmission fluid will be able to escape through gaps and leak away.

3. Damaged Transmission Line

Transmission fluid is carried towards the front of the vehicle through a fluid line, which will usually be made from aluminium or steel. While tough, lines can start to leak if they crack or break, an especially likely issue if they are allowed to become clogged by old or dirty transmission fluid. If you notice transmission fluid leaking towards the front of your vehicle while it is parked, a damaged fluid line is probably the cause.

4. Cracked Torque Converter

Your transmission's torque converter propels transmission fluid into the power system. That fluid provides lubrication and vital hydraulic pressure. However, torque converters can develop small cracks over time, which will allow transmission fluid to leak away.

5. Overheating

Low transmission fluid levels can cause overheating, and overheating can cause low transmission fluid levels. Even when all seals are adequate during normal operation, excess heat can place added pressure on the system and force transmission fluid to leak out. Overheating can occur due to anything from aggressive performance to driving in hot weather, so try your best to avoid such risk factors. 

For more info about automatic transmissions, contact a local professional.