During a normal rebuild, what should be done with transmission cooler lines?

During a normal rebuild of an automatic transmission, it is crucial to ensure that the transmission cooler lines are in optimal condition for the effective operation of the system. These lines are vital as they transport transmission fluid to and from the cooler, which helps to maintain the proper operating temperature of the fluid.

Replacing the lines is often recommended because, over time, they can develop wear, corrosion, or other types of damage that affect their integrity and functionality. Old or damaged lines can lead to fluid leaks, which would impair the transmission’s performance and could lead to more significant issues.

Flushing the lines is also an important step. This process helps to remove any foreign material, such as debris, metal shavings, or contaminants, that may have accumulated in the cooler lines over time. These materials can enter the fluid system and interfere with the transmission’s operation, potentially causing overheating or other mechanical failures.

By choosing to both replace the cooler lines and flush them thoroughly, a mechanic ensures that the entire transmission system is clean, efficient, and less likely to experience future issues related to overheating or fluid contamination. This dual approach is essential for maintaining the longevity and reliability of the rebuilt transmission.