What would cause the overdrive to fail in a 1993 ford thunderbird?

What would cause the overdrive to fail in a 1993 ford thunderbird? - 1

Lack of proper maintenance.

Age and wear, it's a Ford.

AODE transmission in it. Anything from stuck shift valve in the valve body or burnt frictions in the transmission meaning rebuilt transmission needed. Find local shop at ATRA.COM for road test to determine the problem