Hyundai Repair: Hyundai makes intermittant thunking sound, loose tie, seat area

Question
2001 Accent, When coming to stops intermittently the car makes a thunking sound. It sounds as if it is happening under the driver/passenger seats. Could this be a problem with the automatic transmission ?  
2. Car has 64,000 miles should we change the timing belt ASAP ?

Answer
A noise that appears to be in the seat area is probably not a trans problem, More likley a loose tie rod or ball joint. As far as the Timing belt goes, YES change it ASAP. And while it's at the shop ask them about the noise. That would be your best course of action as long as it is in the shop anyway.
Good luck