I want to change the transmission fluid on my 2005 AT RX-8 to Royal Purple ATF and the differential fluid as well. How many quarts will I need to buy. Are there any special parts/tools I need to get? Is the procedure the same as the manual transmission cars (https://www.rx8club.com/series-i-do-yourself-forum-73/diy-transmission-differential-fluid-replacement-35115/)?

 

it is not close to the same, and some issues have happened with the wrong syn atf fluid.....

i would stay with what the maual says. and do a lot of research....

good luck..

beers

 

I flush mine out with Redline ATF where I work. Used about 12qts.
Thought about dropping my pan but the torque converter & lines would'nt drain out so opted for the flush.

 

I use Redline too. It takes a lot to replace all the ATF, about 12 quarts is right. If you only do/get 4 or 5 quarts than you have not done a complete drain and replacement.