The dealer is telling you this? I'm sure your basic warranty has run out but you should have a powertrain warranty on this. You might try taking it to another dealer for a second opinion if you don't trust the diagnosis
According to MSN, powertrain warranty has unlimited mileage and time (towards bottom of page). I would say it's worth your time to check your owner manual bundle to see what the powertrain warranty covers. hope this helps!
http://autos.msn.com/research/vip/Spec_Glance.aspx?year=2...