I mix it 5-6 quarts and the rest dexron 3, so after 4 fluid changes you have used a whole bucket! I recommend every 25K to 30K miles for fluid changes, so if you plan to keep your car that long then it may work out. Most people never change the fluid that often though and ends up around 50K miles. On my old 95 prix with an L67 swap it ran high 12s and it had hundreds of track passes, the majority with drag radials or slicks, and when I sold the car the trans had 35K on it and I serviced it before I sold the car and the pan was spotless and the fluid still looked like the day I put it in. I also used a larger external cooler. That car was raced near every weekend at the track and on the street and had a lot of hard high speed run miles on it. The fluid works, but again a cooler is important. My trans temps were always around 150-170 year round.
