I used Renewable Lubricants in a recent ATF flush of my '03 KIA Sedona (3.5L), at 50K miles. It shifts as good as or better than ever before. I had already done a series of through-the-dipstick pull and refill, to the tune of about 5 quarts, between 30K and 50K, and when we bought the van at 15K we had the dealer do a flush with OEM fluid. I used Maxlife ATF when I did it myself. The Maxlife was fine, better than OEM it seemed by how it shifted, but the RLI seems better yet.