Transmission fluid leaking from Subaru Forester.

Transmission leaks and what can cause them

In Vehicle Fluids by HomeTowne Auto Repair & Tire

Have you noticed gold or red fluid in your garage or on your driveway? This can be a symptom of transmission leaks.

A vehicle’s transmission sends power from the engine to the wheels. The Transmission fluid lubricates components. In addition to gold and red, it can be black or pink.

If you notice any of these colors near your car, reach out to a nearby auto repair shop. You don’t want to wait long to have it checked out.

What causes transmission leaks?

Transmission fluid can leak from different areas.

You could have transmission leaks from the front pump seal and the rear output shaft seal.

Transmission leak on a Chevy Colorado.
Transmission leak on a Chevy Colorado

The pan gasket, solenoids and electrical connectors are possible places, as well. Certain vehicles are infamous for leaking through the electrical connectors.

On a lot of cars, the transmission cooler lines run to the radiator. So, transmission fluid may drip anywhere from the radiator to the transmission.

As they get older, a problem could occur with a bracket that holds the line. Sometimes, the lines rust and start leaking.

Certain trucks and vehicles used for towing have an external cooler, which might go in front of the radiator or have its own cooling fan. Transmission fluid may drain from here too.

Other leak sources include connections on the radiator and  – due to age – the cooler inside the transmission.

Transmission fluid and coolant

It’s important to be watchful of any transmission fluid floating around in the coolant reservoir. That can be an indication that there’s a problem. The transmission will push fluid into the engine coolant in the radiator. 

During an oil change, our technicians will conduct a courtesy inspection. As a part of this process, they check the fluids. The technicians aren’t just confirming the fluid levels – they’re also looking for problems like this.

Under extreme conditions, the transmission may push so much fluid into the coolant that it could appear pink.

Another possible problem that we would like to avoid is the engine coolant going back into the transmission. It’s much cheaper to replace the radiator than the transmission.

Transmission services and replacement

Certain components can be changed when transmission leaks are present.

If the problem is connected with transmission cooler lines or the cooler, new ones may be installed.

Different seals – the tailshaft seals, output shaft seals, and transmission pan seals – and o-rings are also replaceable. The type of seals on a vehicle depend on whether it’s four-wheel or front-wheel drive.

Transmission for Mustang.
Transmission replacement on Mustang

Depending on the location of the leak, a new transmission may be needed. For example, a Chevy Colorado we worked on a few months ago needed a new transmission. We believe the front pump seal behind the torque converter busted. We are capable of putting in new front pump seals, but sometimes it isn’t worth it.

You may also notice certain symptoms if you have a bad transmission, such as trouble switching gears.

A great way to reduce any transmission problems is through regular transmission fluid exchanges. This mileage-based service cleans out contaminants that buildup in the fluid overtime and helps prevent parts from breaking down prematurely.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Lake Ridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.