Automatic Transmission Problem

2001 Hyundai Accent. Has a difficult time shifting from 2 --> 3 gear. Once in 3rd gear stays stuck in that gear, until I turn car off and restart it. Then the problem repeats itself. In the past restarting car fixed it, and the problem only occured a couple times a month. However it had begun happening increasingly frequent in the past 2 weeks, and now I can’t get it to operate normally. Any help or suggestions are appreciated. Thanks

You need to scan the computer for codes before you do anything else.

transman