My car bow has 68000 miles on it, and at the end of a very long drive from New York to Tennessee my transmission started slipping. So after emptying my car out at the hotel I started making the hour long drive to the nearest Mitsubishi dealership when my car popped up a little warning telling me to slow down and about 10 minutes later the car dropped from 75 to 45 mph over 2 more minutes and then it just stopped. I sat for 20 min letting the car cool down and then SLOWLY made my way to the dealership. They have no idea what could be wrong so I have to wait until tomorrow for them to run tests. What could it be? And if I have to replace the transmission how much might that cost me?