See Figures 1 and 2
All Mustangs are equipped with a Vehicle Certification Label attached to the left side door lock post. The transmission code is located in the space marked TR on the label. For more information regarding serial number identification, please refer to General Information & Maintenance of this repair guide or see your local parts dealer.
There are two automatic transmissions used in the Mustangs covered in this information, the AOD and the A4LD. Additional information is located on the tag attached to the transmission case such as service ID, level, and build date.