I decided to go ahead and change the atf in my 190E 2.6 with the pricey Redline D4. There is a noticable improvement by quicker and more positive shifts. It had Valvoline dextron lll in it with only 15K on it. I didn't think there was a problem at all. There was some sludge in the bottom of the pan at that low milelage. I changed the TC and filter also. I'm glad I went with the synthetic redline.