High Fluid Level
WARNING: This page is about a different car, the 2006 Mercury Milan and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
A fluid level that is too high may cause the fluid to become aerated due to the churning action of the rotating internal parts. This will cause erratic control pressure, foaming, loss of fluid from the vent tube and possible transaxle damage. If an overfill reading is indicated, adjust fluid to correct level.