I changed my ATF about a year ago, including cleaning the pan and replacing the filter & gasket. I only drained it once and was going to go back and drain/fill again, since once only gets about half of the old fluid out, but I never got around to it. I finally want to get that done, but since it has been a year (10K miles), I went ahead and ordered a new filter and plan to drop the pan and clean it again. This time I plan to drain, fill, drain, fill. (I only had a minimal amount of sludge in the pan after 90K miles, probably less than a 1/4" of metallic sludge on the magnet)
I'm trying to decide if I should replace the filter after the first drain or the second. On the one hand, the initial drain could reveal more sludge in the pan that could get stirred back into circulation when refilling. On the other hand, waiting to replace the filter until the 2nd drain would leave the new filter with less contaminants in the end. Does that make sense? What would you do?
I have 7 quarts of Mobil Dexron VI (synthetic blend) left over from the case I bought last year, so I need to get more of that. Looks like best price is still The Lubricant Store, at $55.44 a case:
Mobil ATF Dexron VI (Case - 12 Quarts)