I own 2008 MAZDA6 . I always try to keep up with the maintenance required by Mazda. However, upon checking with manual service book, I didn't see any transmission fluid flush / exchange required in the book. By any chance, does any of you know when this transmission fluid is due to be replaced?

 

well, I think it is up to the owner. The transmission fluid should have a red/light brown color. If you find that the color of the fluid is black, get it changed. I had my changed at 50,000 just as a precaution. If you have an manual, I would not worry about it unless you drive it hard. However, I have a 4-speed automatic and I drive it hard from time to time, so I changed the fluid at 50,000. Still runs well at 81,000 miles.....

 

I've worked in vehicle development for over 20 yrs. We never change trans fluid on our durability cars. If you have over 50k on your transmission, I wouldn't change it at this point.

 

My mazda 6s changed twice. The first time was 30,000 miles. The second time is 45,000 miles. I only did transmission oil change not transmission oil flush.
My mechanic told me the transmission was turn to dark during 45,000 miles.

I suggest using genius mazda transmission oil. It is not cheap.

My other car - ford five hundred 05 did transmission oil change every 30,000 miles.

 

It's not just a suggestion, but a requirement that you use Toyota T-IV ATF in the Asian AW 6-speed auto. Ford also sells it under their Motor Craft brand (the Fusion/Millan used to have the same transmission). I'd avoid using those "multi-vehicle" fluids. Mercon is a definate no-no.