Just a guess but there is a relay that controls car shifting out of park when brake is pressed. Think it's in center console region. Could also be a relay acting up for the overdrive issue. Maybe they are both in same area and have a common wiring issue.

 

I have a 97, and I know mine has a shift lock solenoid. This is what prevents you from taking the vehicle out of park inless you have the foot on the brake. I was thinking that may be the problem.

Can anyone with a haynes manual check and see where to look for the relays? Also give me an idea if the overdrive is tied into the same wiring somehow?