The fluid has broken down to the point where its hardly protecting at this point. People come into my work with high mileage all the time and get a Tranny flush with no problems. however there has been one time there was a problem on a car that was over 150k. but it was shifting like shit when it came in. so i dont know either continue letting the fluid brake down even more and face having to replace your tranny or get it rebuilt sooner. or take the little risk and flush it.