One problem related to transmission solenoid has been reported for the 1997 Hyundai Sonata. The most recently reported issues are listed below.
Automatic transmission; when appling gear in reverse there is a hard banging noise coming from transmission. Transmission has been replaced three times. Dealership was aware of problem. Check engine light illuminated, dealer replaced faulty O2 sensor. Faulty battery causing vehicle to crank slow. Driver door window moves slow, dealer lubricated glass channel. Outer cv boot replaced, it was cracked. Solenoid valve faulty causing poor gas mileage.