Hello. Last time I went to replace the ATF of my Toyota Land Cruiser automatic transmission, the mechanic replaced the stock radiator with an aftermarket one that was supossed to be better. The results were terrible, it was ok in overdrive (it has 3 speeds plus overdrive) as the torque convertor was locked, but, as I had to slow down and running up a mountain pass, the temperature started to raise easyly over 212ºF and I reached peaks of 266ºF. As I was very busy at the time and the automatic transmission specialist was far from me, I had to drive the car for a month and completed 2000 miles. Hopefully, most of them were on the highway where the temperature remained under 190ºF, but I reached the 266ºF at least 3 times. and temperatures like 240ºF quite often. Just peaks as I stopped as soon as I realized but there they were. Now I have fixed the cooling system and I stay under 175ºF most of the time with maximums of 210ºF, but I've been told that the oil can be damaged after having reached those temperatures. It's a fully synthetic Dexron III, that should be able to stand higher abuse, but I don't know to what point. It looks and smells like new, so I guess it's not burned, but maybe it has formed varnishes what is hard to tell as I haven't got any place to analise atf here. The oil is only 4000 miles old now. Do you think I should change it before it damages my transmission, or should I wait till the next oil and filter change (I do it every 15000 miles). Thanks in advance.