I took my WJ into the dealer to get an oil change before my last roadtrip (didn't have time to do it myself). Anyways after their "21 point check" they said that I need to change my transmission fluid. My last XJ I never changed it and drove it for 100k, no real issues. Should I change it? My WJ has 59k on it. I took the WJ on a 600 mile trip fully loaded with 4 people and enough ski gear for 10. It was shifting somewhat hard on the hills but nothing too crazy. Any thoughts?