Why won't my 2004 Ford Freestar go into reverse but it drives?

Why won't my 2004 Ford Freestar go into reverse but it drives?

It is most likely a specific type of transmission problem. You seriously should stop driving it and take to an auto shop. It will cost you a lot of money if you wait.

Internal transmission issue such as a sticking reverse clutch or malfunctioning solenoid or valve body problem.