How does transmission fluid get low?

How does transmission fluid get low?


Transmission fluid plays a crucial role in the smooth operation of a vehicle’s transmission system. It serves as a lubricant, coolant, and hydraulic fluid, ensuring that the gears and other components work together seamlessly. However, over time, transmission fluid levels can drop, leading to potential issues with the transmission. In this article, we will explore the various reasons why transmission fluid can get low.

Normal Wear and Tear

Normal usage: One of the primary reasons for low transmission fluid levels is normal wear and tear. Over time, the transmission fluid can break down and lose its effectiveness. As a result, the fluid may become thinner and evaporate more quickly, leading to a decrease in fluid levels.

Leaking Seals and Gaskets

Seal and gasket deterioration: Seals and gaskets are essential components in the transmission system, preventing fluid leakage. However, these seals and gaskets can deteriorate over time due to age, high temperatures, or other factors. When this happens, transmission fluid can leak out, leading to low fluid levels.

Cracked or damaged transmission pan: The transmission pan is located at the bottom of the transmission and holds the fluid. If the pan becomes cracked or damaged, it can result in fluid leakage and subsequently low fluid levels.

Transmission Cooler Line Leaks

Corrosion or damage: The transmission cooler lines are responsible for carrying transmission fluid to the radiator to be cooled. Over time, these lines can develop leaks due to corrosion or physical damage. When the lines leak, transmission fluid can escape, leading to low fluid levels.


Excessive heat: Transmission fluid is designed to withstand high temperatures. However, if the transmission becomes overheated due to heavy towing, stop-and-go traffic, or other factors, the fluid can break down and evaporate more quickly. This can result in low fluid levels.

Incorrect Fluid Level Check

Improper checking procedure: Checking the transmission fluid level requires following the correct procedure, which may vary depending on the vehicle’s make and model. If the fluid level is not checked accurately, it can lead to an incorrect reading and the mistaken belief that the fluid is low.


Low transmission fluid levels can have various causes, including normal wear and tear, leaking seals and gaskets, transmission cooler line leaks, overheating, and incorrect fluid level checks. It is essential to regularly check and maintain proper transmission fluid levels to ensure the smooth operation and longevity of the transmission system.