If the transmission oil leaks out of left side half shaft area, it may be from a worn axle shaft seal. The seal can be damaged by a poor surface finish on the axle shaft. The axle shaft and seal should be replaced to correct the problem.
2012 Ford Fusion Problem Reports
RepairPal Verified 2012 Ford Fusion Problem Reports
The automatic transmission may develop shifting concerns. On lower mileage vehicles, upgrading the software in the powertrain control module (PCM) and the transmission control module (TCM) may correct the problem. As the mileage increases, internal transmission damage can occur. Repairs could involve replacement of the valve body or a complete transmission rebuild. Whenever major transmission repairs are made, it is important to be sure the PCM and the TCM have the latest software updates to help prevent these issues from reoccurring.
Electrolysis can cause repeated failures of the heater core and radiator. The diagnosing technician should check for voltage present in the coolant, with the battery disconnected, because electrical current in the coolant causes electrolysis. Corroded or deteriorated parts should be replaced, and the coolant should be flushed. Ground straps can be added to help prevent future corrosion of components.
The electric trunk latch solenoid can get stuck in the open position making it so the trunk will not latch closed. The diagnosing technician should verify correct electrical connection at the solenoid and check for correct cable routing. The trunk latch most commonly will need to be replaced.