Having some problems with my transmission. The overdrive lights on the gearshift blinks almost all the time...Sometimes it will keep shifting in and out of overdrive and sometime slip in overdrive. Any suggestions on what this may be? What transmission is in this truck and what years fit this if i need to replace? Thanks for all your help...It has a 7.3 diesel with turbo.

 

you need to pull the codes that are stored in your trucks computer! This will put you down the right path to figuring it out. It could be something simple like a sensor. Trans is an E4OD

 

Codes, My WAG is the FIPL (IDIs version of a throttle position sensor).

ON EDIT:

Resist driving it until you fix it, E4ODs are easy to break when in limp home mode (or high pressure mode for that matter) and expensive to fix if you kill them.
90-97 diesel E4OD will fit, but only the torque convertor for an IDI will fit, IDI used 4 studs, PowerStroke used 6, and the flexplates are NOT interchangeable

By the way, does the speedo work? How about the tach?

 

the speedometer works until you get to about 55 then it starts bouncing all over the place...the tach works most of the time When the truck is idleing it sometimes reads zero but as soon as you hit the fuel it bounces and seems to work properly! what could cause this...I know the speedometer is just a cable right?

 

what is the easiest way to pull the codes out of the computer?

 

Is your engine an IDI diesel or a Power Stroke?
Your speedo is not cable driven but electronic, driven by the vehicle speed sensor (VSS) on the rear differential housing.
Oops, my bad, as auto must be an IDI diesel.
http://www.troublecodes.net/Ford/ Wire in a small test light as shown here, turn key to on and light will flash out the codes. Hold gas pedal to the floor during the test (engine off) otherwise you will get a false TPS code.

 

Tach sensor is bad, pull the VSS and clean it, that may help your speedo.

The trans needs a properly working speedo and tach to work.
Signal goes to your PSOM (speedo) before the computer for the trans.

P.S. If you go to the part store for parts for that engine tell them it's a 93, 94 was the first year for the powerstroke so when you tell them it's a 94 there computer assumes it's a powerstroke but since you have an auto we know you have an IDI.

 

So I need a vss sensor and a tach sensor is there a certai names for these at the dealership we all know that they have different names for stuff

 

Where is the tach sensor located? Would be the same as a cam or crank sensor?

 

The tach sensor is beside the engine oil fill cap. Looks like a big hex nut with two wires to it. It is not the same as a cam or crank position sensor.
If asking for parts ask for a VSS for the rear diff and an engine speed sensor for the tach.