More probable causes include:
* Transmission cooler lines: These lines carry coolant through the transmission to cool the transmission fluid. A leak in these lines would be a common place for a coolant leak near the transmission and engine. These are often rubber and can degrade over time.
* Intake manifold gasket: While less likely to be directly *between* the transmission and engine, a leak in the intake manifold gasket *could* manifest in that area, especially if the leak is traveling downward.
* Engine block crack (in a less visible area): A crack in the engine block near the transmission mating surface is possible, although less common than the other options.
* Water pump: While generally seen on the outside of the engine, a very small crack or seal failure could cause coolant to seep towards the transmission.
It's crucial to have a mechanic diagnose this. Trying to pinpoint the leak source without proper inspection can lead to further damage and unnecessary repairs. The leak is internal and difficult to find visually, likely needing a pressure test to determine the location and source of the coolant loss. Ignoring it will lead to overheating and potential catastrophic engine damage.
