RE: O/D wont shut off
Zack, the wiring is most likley broken inside the console in the shift handle area. It's an easy DIY fix usually.
The button switch is a normally open momentary switch to ground which signals the PCM to allow or not allow 4th gear which is overdrive at 0.7:1 ratio. The wiring that goes up the inner part of the shifter handle is small and usually gets broken at the base of the shift lever from the incessant flexing.
If you do a search, you can find instructions posted on removing the console(and shifter handle if necessary) to allow access for the repair.
On a rare occasion, the button switch itself could actually be broken.