96 econoline / no overdrive

You will note that there isn’t a drive position on your gearshift indicator. However, you will find a Transmission Control Switch and an indicator light labeled “Overdrive” located on the end of the gearshift lever. Press this switch and the word “OFF” will illuminate on the shift lever knob. With the word “OFF” illuminated, the transmission will operate in gears one through three.....................pasted from the owners manual for your van. Check to see if it's simply turned off.

Needs rebuilt transmission

I had a Ford F-150 that had the over drive button on the gear shifter. It shorted out and the truck would not come out of overdrive. Come to find out Ford had run the wire in the gear shift and what happens is the wire gets pinched where it comes in at the steering column. When this happens it cuts the wire completely and doesn’t cause any issues other then it will not go into overdrive or it will short out and the vehicle will never come out of overdrive. With out more info I am assuming you don’t have overdrive or a mechanical issue.