Are the automatic transmissions interchangeable between a 1988 and 1994 Ford Aerostar?

No, the automatic transmissions are not interchangeable between a 1988 and 1994 Ford Aerostar. The 1988 Aerostar used the A4LD (AXOD) transmission, while the 1994 Aerostar used the 4R44E transmission. Although both these transmissions have four speeds, they have different internal components and cannot be swapped without extensive modifications.