transmission issue

[nycdom]

i have a 2000 i30 that when i start driving, the car shifts well, after about 15-20 miles it doesnt go into overdrive at highway speed, when i let off the gas it almost seems like its going into neautral. wen i hit the o/d switch it does nothing. please help

[maxhopper]

The first thing to check is the trans fluid level. If that is ok, make sure the overdrive/check engine light is working. If you have no warning lights, or stored codes, I would suspect a valve body problem, although it could be worse.

[nycdom]

transmission fluid levels looks good, my ses is on, but has been on before the o/d issue it was a coil pack that was setting it off. can it possibly be the solenoid?