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The fluids in your transmission need to stay clean and cool for your vehicle to work properly. Transmission line connectors help this happen by forming the junction between your transmission, lines, and transmission cooler.



What are Transmission Line Connectors?

Transmission cooler line connectors are the interface between your transmission, lines, and transmission cooler.

These connectors often wear out due to age, vibration, and excess heat. Their life may be extended with regular transmission maintenance, including visual checks and fluid changes.

How do Transmission Line Connectors Work?

The connectors form a tight seal between transmission components. One connector attaches the line to the transmission, and the other connector attaches the same line to the transmission cooler. Failing connectors are one of the most common sources of fluid leaks on many cars and trucks.

Diagnosing leaky transmission connectors is often as easy as locating them and visually inspecting them for wetness or fluid spray.

How are Transmission Line Connectors Made?

Line connectors are most commonly made of steel. They are attached to your vehicle’s transmission lines with a compression fitting made to withstand temperature, pressure, and automatic transmission fluid (ATF). The fitting between the line and the connector often requires special tools and machinery to create.

If you find one of your connectors needs to be replaced, often your only choice is to buy a new transmission line to replace the old, leaky one.

What Causes Transmission Line Connectors to Fail?

  • Vibration causes connectors to loosen up over time.
  • Vibration causes connectors to crack.
  • Vibration and heat damage the rubber compression fitting attaching the connector to the line.
  • Over tightening the connectors during a past or recent line replacement.
  • Under tightening during a recent line replacement.
  • For some applications, failure to properly dress the connector fitting with tape or sealant may cause it to leak prematurely.

Common Failure Symptoms

  • ATF spots or puddles under your vehicle. ATF is often red, reddish, or brown in color. ATF has a very distinctive smell, especially when it wears out, whereas motor oil typically has very little scent regardless of age or use.
  • Transmission overheats, slips, or becomes damaged.

What Happens When Leaky Connectors Aren’t Fixed?

  • Property damage in the form of stained driveways, roadways, and parking lots.
  • Left unchecked, a leak may starve your transmission of fluid. Your transmission may overheat, causing premature wear or even major damage.

Even small leaks deserve attention. Seemingly small problems, like fluid leaks, often turn into much larger problems without warning. If you find your vehicle leaks oil, coolant, ATF, or even fuel, you must diagnose the problem as soon as possible.

If you have questions or concerns about transmission line connections or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.