I've done a 2 qt. trans fluid change w/ T-IV fluid. How do I completely change out the 8.7 qts of fluid? I know the fluid has never been completely changed. I have 179,000 mi. I plan on purchasing & installing Lexus rebuilt 2800 rpm performance converter in the future. Should I just change 2 qts every 500 miles 6 times? I got 12 qts @ $6.50 per.