Here's why:
* Transmission Cooler Location: The automatic transmission in these cars uses a radiator-style cooler, often integrated into the main radiator. Coolant flows through this cooler to lower the transmission fluid temperature. The lines connecting this cooler to the transmission run very close to, and sometimes even through, the engine compartment's tight spaces near the engine and transmission mating surfaces.
* Line Failure: The cooler lines, being rubber or rubber-coated, are susceptible to age, cracking, and deterioration. These lines can develop leaks, especially in areas that flex or experience vibration. A leak in this area might *appear* to be between the engine and transmission, when it's actually from a line.
* Cooler Failure: The transmission cooler itself can also fail, leading to leaks. This is less common than line failures, but a crack or rupture in the cooler will certainly cause a coolant leak in the area you describe.
* Intake Manifold Gasket (Less Likely): While less probable, a severely damaged intake manifold gasket *could* cause a coolant leak near the engine/transmission interface. However, this would usually manifest as a coolant leak more obviously associated with the engine, and coolant might enter the intake system, leading to different symptoms.
Troubleshooting:
To diagnose the exact source of the leak, a thorough inspection is needed. This likely requires:
* Visual Inspection: Carefully examine all coolant lines near the engine/transmission area. Look for cracks, corrosion, or wet spots.
* Pressure Test: A pressure test of the cooling system can help pinpoint the leak's location within the system.
* Transmission Fluid Check: Check the transmission fluid for signs of coolant contamination (milky appearance). This indicates a definite cooler or line issue.
Important Note: Mixing coolant and transmission fluid is extremely detrimental to the transmission. If you suspect a leak, address it promptly to prevent severe transmission damage. Continuing to drive with such a leak can quickly ruin the transmission.
