What is the leading cause of automatic transmission failure?

Overheating is a significant factor leading to automatic transmission failure because transmissions rely on fluid to provide both lubrication and cooling. When a transmission overheats, it can cause the fluid to break down, leading to a loss of its protective qualities. This breakdown can cause wear on internal components, such as seals and clutches, resulting in erratic shifting, slipping, or complete transmission failure.

Overheating can occur for various reasons, such as towing heavy loads, low fluid levels, or failure of the cooling system. While low fluid levels and contaminated fluid can contribute to overheating, they are often secondary issues. Additionally, while poor driving habits can lead to premature wear and tear, they typically do not cause immediate overheating. Therefore, addressing potential overheating issues is crucial for maintaining the longevity and performance of an automatic transmission.