The overdrive is designed for speeds after 50 mph so your overdrive should not be engaged until you are driving on the highway. The overdrive gear is designed for fuel efficiency and does nothing in town.
First the gear could be out. The other issue could be with the linkage itself in the transmission thus it won't go into overdrive.
It is a recall. You should take it to a ford dealer. They will take care of it. Here is a link, that shows recalls for The Thunderbird. http://www.dealerrater.com/recalls/Ford/THUNDERBIRD/
Overdrive allowed is the normal position
Ford Thunderbird was created in 1955.
On a 1990 Ford Thunderbird : There should be an EEC TEST connection in the engine compartment for the OBD I , EEC IV system
No, the latest ford thunderbird was produced in 2005. after that, they were discontinued :(
Mercron transmission fluid is used in a 1978 Ford Thunderbird. Type F fluid can also be used but should not be mixed.
The people at Ford should be able to tell you
No. You should not drive in overdrive all the time.
Overdrive is the normally allowed position ( it won't shift into overdrive until the speed is fast enough )
what are the fuses in a 1986 Ford Thunderbird and what do they do
The Ford Thunderbird door should trigger the lights to go off. The sensor associated with the closed-door may need to be replaced.