Changed the transmission fluid in my 05 Mazda6 s last night.
At 62000 miles I expected it to be a bit dirty, but it was pretty brown. I was surprised because when checking the dip stick and wiping on a white paper towel, it doesn't look too bad, still has some pink color to it. The fluid that came out was definitely more brown and nasty.
I refilled with Castrol Import, Type T-IV compatible. It was about $5 a quart, half the price the dealer wanted for the genuine Mazda stuff. Hope this is OK - anyone have comments on this?
I just did a drain and fill and it was very simple on the 6s.
1. Jack up car.
2. open drain plug - you need a 10mm allen wrench to do this. I used a 10mm allen socket that worked great. It was not on too tight at all (has never been opened). Drain into a container that you can measure how much to put back in - this will save a lot of guess work later. Let the jack down during this process and you might get some more to drain out. I got about 3.5 quarts out - about half the total capacity.
3. Replace drain plug and refill through dipstick. I couldn't find a fill port, I'm sure it has one somewhere, but it definitely is not easy to access/find. Used a long neck funnel and had to lift/angle the funnel a bit to let air out while filling.
I'm planning to do another change in the next couple thousand miles, just to get more of the dirty fluid out. At least the fluid in there is now half as dirty as before - not sure if it all mixes nice.