I was told by the mazda dealership that i would need like 13 quarts of transmission fluid for a flush. Just wondering if this is true and if you should any mechanic be able to completely flush my system and replace ALL the fluid or should i take it to the dealership and let them handle it. I have approx 54,000 miles on the MPV right now.
I was also reading some of the posts that stated that you could replace about 3 or so quarts just by removing the drain plug on the trans, and if you do this a few times over a couple of months that maybe you would have FRESHER fluid in the tanny, not completely new, but maybe better than what it is now.

 

The fluid capacity of 04 MPV transmission is 10.3 quarts. Any shop with a decent flush machine can do the same job as dealers. They all pretty much work on the same principle. Trans oil pumppushs the fluidinto a dual chamber cylinder divided by a flexible diaphram. The fluid going in on one side puts equal pressure onto other chamber with new fluid and this is pushed into the system.
You can drain a little over 3 quarts by doing a simple drain and fill but if fluid has not been serviced well and is discolored and getting burnt you will just be dilluting it down a bit. If fliud is in good conditiion then this is a very good regular maintenance practice. Did you see the post about doing the fliud flush by yourself. It works pretty close to a flush machine in my experience.

https://www.mazdaforum.com/m_41453/tm.htm