1994 sonata will not shift overdrive

Can anyone help me diagnose my 94 sonata 1.8? If the overdrive is on, the car will not shift to its final gear. It tries, but it's like the car goes into neutral and the engine just races. If I hit the OD-off button, the car works fine in its first 3 gears. Is there a fuse or relay that I can check?
J

actually it's an elantra, not a sonata... I'd imagine they work about the same, but I'll post in the elantra forum. Any help would be appreciated.
THanks,
J

I would suggest to take it to a mechanic you trust or at the dealership, cause if you do not know what model vehicle you have you might make a mis-diagnosis.

Moving thread to Elantra forum

TS out