What is the purpose of cooler lines in an automatic transmission?

The purpose of cooler lines in an automatic transmission is to connect the transmission to a radiator-mounted transmission cooler. This setup is critical because automatic transmissions generate a significant amount of heat during operation, which can lead to decreased performance and potential damage if not managed properly. Cooler lines serve to transport transmission fluid from the transmission to the cooler and back again, allowing the fluid to dissipate heat before it re-enters the transmission system. This process helps maintain optimal operating temperatures and ensures the transmission operates efficiently.

The other options do not accurately describe the function of cooler lines. For instance, connecting the transmission to the fuel tank or supplying fluid to the transmission pump does not involve cooler lines, as those components have specific roles that do not pertain to temperature regulation. Similarly, while circulating fluid is a function of the transmission itself, cooler lines specifically facilitate heat exchange rather than being responsible for the overall circulation of fluid within the system.