Today I flushed the auto trans in the brick. Hats off to the info contained in the FAQS here on how to do it, the job set me back a hair over 20 bucks including a case of dexIII and hose and clamp from Home Depot. Now my question/thought- I flushed it today with 12 quarts and to be real anal I plan on doing it again after next engine oil change(in 1500 miles or so). My plan is to flush thru another case of dino oil and then add synthetic into the system. So as I'm doing this, pumping two quarts out and then adding two quarts of synthetic and repeating etc. Are I not just mixing the synthetic with the dino oil? I guess what I am asking is will I ever have truly synthetic oil in there or will it always be mixed using this method? My thoughts are to use one case of dino and 8 quarts of synthetic at the end. Questions like this keep me up at night, God help me..Happy New Year everyone..