Harsh or Delayed Shifting of Automatic Transmission on Mercury Milan

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.