Causes of a Transmission Leak

Transmission leaks are the bane of all car owners. Transmission leaks can seriously damage a car's transmission if left unaddressed. What follows is a brief description of the most common causes of a leaky transmission.

Worn Transmission Pan Seals

A transmission pan is responsible for storing transmission fluid. It has a rectangular seal that separates the bottom and top parts of a transmission pan. If this seal cracks or frays, transmission fluid will leak out of a transmission pan and cause a transmission leak.

Worn Rear Main Seal

A car's rear main seal is a very important engine/transmission seal that marks the junction where a car's transmission and engine link together. A rear main seal that becomes worn, frayed or cracked will allow transmission fluid to leak out, causing a very troublesome and hard-to-repair transmission leak.

Cracked Transmission Fluid Line

Transmission fluid travels throughout a transmission via a long, slender transmission fluid line. This transmission line is normally made up of steel and/or aluminum. Although very solid and structurally sound, a transmission fluid line can become damaged from road debris, impacts or excessive heat, and develop breaks or cracks that cause a transmission leak.

Leaky Torque Converter

Although a much less common form of transmission leak, a leaky torque converter can result in a significant amount of lost transmission fluid. A torque converter is a hydraulic pump that pressurizes and propels transmission fluid throughout an entire transmission. Leaks or cracks within the body of a torque converter can cause a serious transmission leak.

Loose Transmission Pan Bolts

Perhaps the most common type of transmission leak is caused by a loose transmission pan. A transmission pan is held in place by a series of bolts that have to be tightened sufficiently to avoid transmission fluid from leaking out. Loose or damaged transmission pan bolts can result in a loose-fitting transmission pan that results in a transmission leak.