Mitsubishi Repair: 95 mitsubishi 3000gt auto overdrive, mitsubishi 3000gt, transmission control unit

Question
1995 Mitsubishi 3000GT sl? auto trans

Just recently purchased this car for my nephew, as was picking it up seller said the automatic overdrive isn't working and when it goes in that gear the car goes into neutral.  Am very concerned about the rest of transmission as he must drive it home, 6 hour drive. The transmission seems fine when we drive it locally.

Thanks for some advise

Answer
Jennifer,
If the overdrive is left turned off, and the car drives fine, it should be fine for highway driving.  As long as the RPMs do not go above the red line mark, then your engine shouldn't suffer any damage.  Though after the car is brought home, the car should be looked at by a transmission specialist.  The most probable cause for this issue is a malfunctioning overdrive control switch, or there could even be a problem with the transmission control unit (TCU).  Both should be inspected by a transmission specialist.  Look in your local yellow pages for a transmission shop in your area.  The average local garage mechanic may not be qualified enough for a transmission as complicated as the one in the 3000GT.
Good luck!