electronic transmission servo? stuck in 3rd!

Greetings!
I'm mulling over the idea of buying a '96 with 138,000. The transmission in it is supposedly a re-man and only a year and a half old. Its only forward speed, apparently is 3rd gear. Still has reverse, park & neutral, but it starts out in 3rd gear and stays there. The dealer said he didn't drive it long enough to see if it shifted to 4th but he didn't think that it would.

He says that his shop tells him it's an electronic servo that's the problem. Any thoughts on this? Also, do these cars have timing belts, chains, or gears? If it's a belt, is the car an 'interference' engine? If the belt was never changed, I wouldn't want to risk driving it if it's an interference engine that could blow up if the belt broke. Unfortunately, I'm too far away to drive it, but the car might be a good deal if someone on this board can verify somehow that the transmission might actually only need a 'small' repair.

Thanks in advance!