Automatic Transmission Upshift Problem
 

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.

The third gear on this model (like the one i have) tends to hold for long when you aer climbing a hill. i noticed this. However, since you are saying that you noticed a behavioral change in the shift, it makes me worried a little... with my old pathfinder, when this happened, i ended up with a transmission failure after few months... but i can't recommend to change the trans fluid, since at 174000miles it might make things worse...