I recently purchased a 2018 GT from a friend. It has 102,000 miles on it. Most all are road miles as his wife had a daily 100 mile commute to work. They purchased it new and all maintenance has been done at dealership. They gave the service records to me. Oil changed every 5000 miles, filters at regular intervals. At 90,000 miles they had new belts, battery, plugs, and induction service done. My question is the AT fluid was never changed. With these amount of miles should I do a drain and refill, or leave well enough alone. Transmission shifts fine.