See posts 8 and 14 on this thread: https:/
/ It refers, latterly, to the TSB that is likely applicable to your '12. I think that it is applicable to all SkyActiv C66M-R 'boxes... CX5, M6, M3, maybe M3.
Also, see this: http:/ www.mazda6club.com/ threads/ synthetic-mtx-fluid.441797/ / This fellow believes that the shift cable neutralization worked wonders for him. See also the graphic, attached. forum.mazda6club.com/ mtx-transmission-discussion/ 297825-crunchy-manual-transmission-6.html