I've been reading into changing the ATF in my cruze lately and have decided I want to try to change it every 40k or so. However I'm not mechanically savvy whatsoever and I don't think I should attempt this myself. I hear a lot of bad things about flushes and it seems to be what all places are telling me they will ONLY do and to do it or nothing at all. My main question is should I have them flush it at a local auto shop (about $140 for Dex 6). Or not trust it and have the dealer flush it, or just find a dealer that will drain and fill?