Hyundai Repair: transmission, rest of the day, historically

Question
Hi
I have a 2003 automatic accent with about 105,000 miles on it.
it will not shift into the highest gear after the car has been sitting over night or a few hours.
If I pull over and manually shift from low to 2nd then drive it goes into gear. I am a courier and drive it all day. After its been running for a while its fine for the rest of the day.
What do you think?
Jackie

Answer
Historically a Hyundai trans usually acts worse when hot when it has failed. I would check the fluid level, hot idling in neutral, not park. If that's ok then I woild have the computer scanned for codes. there may be a sensor that is causing the trouble.
If all that is inconclusive then I would have to say the trans is shot.
Hope this helps