How to Tell if Your Car is Leaking Transmission Fluid – and What to Do About It

If your car is leaking transmission fluid, it is essential to take care of the problem quickly. In many cases, a transmission leak occurs because of a relatively easily remedied issue. However, costly problems can develop if you continue to drive with low transmission fluid.

Your transmission can leak transmission fluid for a number of reasons. There may be a hole in the pan, the seals around the gaskets may be worn due to age, or the plugs may not be fully tightened. If you are unsure as to whether your transmission fluid is low, here are three of the most common signs to look for:

  1. Fluid puddles under your vehicle. Perhaps the most common sign of a transmission leak is a puddle of transmission fluid beneath the car. Unfortunately, it can be challenging to distinguish transmission fluid from other types of fluid. Transmission fluid is red, rust-colored, or brown. If the fluid is green, it is most likely coolant. If it is dark brown or black, it is probably oil.  Some types of antifreeze fluid or windshield wiper fluid can also be red, so you will want to touch the fluid. Transmission fluid will be slick and oily to the touch. It also will smell like petroleum or have a slightly burnt smell. 
  2. Your transmission starts slowly or is difficult to shift. Your transmission relies on fluid to start and operate correctly. If the fluid is running low, your car may lag or shake when it shifts. These issues may signal other transmission problems, as well, so it is important to get your vehicle checked out as soon as possible.
  3. Transmission fluid consistently runs low. In older cars, you can use the dipstick to check transmission fluid levels. In newer cars, a check fluid indicator light will come on. Transmission fluid should be replaced every 50,000 to 100,000 miles, and a properly running transmission will not require you to top off fluid between routine flushes. If you find yourself needing to do so, you probably have a leak.

Transmission fluid is the lifeblood of your car. It removes heat from the transmission’s internal components, and it actuates gear changes through hydraulic pressure. For these reasons, low transmission fluid is something you should never ignore.