Lately I've noticed that the car takes longer to shift from 3rd to 4th. In particular when I climb a hill. I turn onto the main road and immediately climb a hill. Level roads the shifting seems normal. I have traveled the same road out of the neighborhood every day for 12 years and the past 10 years with this car so it makes me think there is something 'beginning' with the transmission. Has anybody experienced this kind of problem? It's an '02 E53 3.0i with 171,000 miles on it.