My '98 4Runner has 188k miles. I've only owned it for 6 months. It seems to have been very well maintained. I spoke to the the only other owner (a woman who drove it 30 miles each way back and forth to work) and she "says" it always had the fluids changed. I spoke to her mechanic, small town, do-it-all type of guy who I do not know. He agrees that she always maintaned it with him, but he does not keep records. The transmission, along with everything else, works flawlessly. My Toyota dealer says the ATF looks to be pretty fresh. However, I'm using it mainly to pull our camper. I've read two thoughts---at this mileage leave it alone, or, go ahead and maintain with ATF change. We have a good Toyota service dept here and that is who would be performing any AT maintenance. Thoughts?