I will be buying a 2000 Focus station wagon from my father in law. He says the tranny slips while going uphill. I've never been in the car so I am taking his word for it. He took it to the dealer twice but they couldn't find anything wrong with it. Any ideas of what could be causing this? Respond here or email me directly at adam.threeofclubs@gmail.com.

Thanks in advance,
Adam