Transmission fluid lubricates each component of your transmission. In a vehicle with an automatic transmission, the fluid acts as a coolant, a power transmitter, and lubricant. Sometimes you can tell that your car is leaking transmission fluid because it will leave a trail and puddle of reddish fluid underneath the vehicle. Or, sometimes your antifreeze/coolant will appear to be a strawberry milkshake.
Common reasons for this to happen:
Punctured or loose fluid pan: The transmission pan is at the bottom of your transmission, and it holds all the transmission fluid. Because the underside of the pan is exposed, it can become damaged and punctured by road debris. The pan can also be loosely secured, which creates cracks and crevices from which the fluid can leak. Depending on the transmission, these pans can be on the side or back of the transmission.
Loose drain plug: At the bottom of the transmission pan is a plug for when the fluid needs to be drained out of the system. If this plug is not properly secured, the fluid will excrete out of it. This plug may also be a fill plug. Newer transmissions take a special tool to fill these types of transmissions.
Damaged pan gasket: The pan gasket is a mechanical seal between the transmission oil pan and the transmission itself. A damaged gasket is a common problem and can be a straightforward fix.
Cracked fluid lines: Transmission fluid travels from the transmission to a cooler via fluid lines. Because these lines and hoses are constantly exposed to extremely high temperatures, they can grow rigid over time, which makes them prone to cracking. Debris that flies up from under the car can also cut these fluid lines.
Bad seals: There are a lot of components within the transmission and each has a seal to keep the transmission fluid from leaking out. These seals can become rigid or damaged and stop doing their job. The most common seals credited with transmission leaks are the seal around the dipstick (where you check your transmission fluid levels), the speedometer o-ring (which attaches the speedometer to the transmission), the seals around the input and output shafts of the transmission, and the front pump seal.
Damaged torque converter: Cars with automatic transmissions have a torque converter instead of a manual clutch. It is a hydraulic pump that builds pressure in the transmission, and is responsible for sending fluid throughout the transmission system. The converter can crack or have faulty needle bearings, both of which will result in leaks.
Damaged transmission oil cooler: Your transmission fluid flows through a cooler, which is sometimes located in the radiator, while others are external. This keeps the fluid temperature down so it does not damage the internal parts. If the cooler is inside the radiator, then you could leak fluid into the antifreeze, creating a fluid that looks like a strawberry milkshake. Sometimes the coolant will mix directly inside the transmission.
What to expect:
A top-rated mobile mechanic will come to your home or office to determine the source and cause of the transmission fluid leak, and will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done:
The mechanic will inspect your car based on where the leak is occurring. Sometimes the dripping of the transmission fluid can tell a mechanic exactly where the leak is. Other times, the fluid will follow a path of least resistance and travel to a different area. If it is a loose part, the mechanic will tighten it, and if it is a cracked or damaged part, the mechanic will have to replace it and will provide an estimate for the work.
How important is this service?
Having your transmission leak taken care of is very important. Without adequate fluid levels, the transmission can become greatly damaged, and the transmission, like the engine, can sometimes be very labor-intensive to repair. Having the leak addressed in a timely manner can greatly prevent internal damages to the transmission that could lead to higher costs later on. Book a mechanic to perform a thorough inspection as soon as possible.