Here's why:
* AOD was the standard automatic: The AOD was the common automatic transmission in Ford vehicles, including the Mustang, during the late 1980s.
* Other options were less likely: While the C4 transmission (a 3-speed automatic) was used in earlier Mustangs, it was less likely to be found in the '89 model with the 2.3L engine and automatic overdrive. Other options like the 4R70W (used in later Mustangs) were not available yet.
However, it's always best to double-check:
* Vehicle identification number (VIN): The VIN can help determine the exact transmission used in your specific car.
* Service records: If available, service records might mention the transmission type.
* Looking under the car: While this may be difficult, you can sometimes identify the transmission by its physical appearance and markings.
By checking these sources, you can be certain about the type of transmission in your 1989 Ford Mustang.
