Postby Big Z » October 10th, 2012, 10:49 pm
That depends on your budget and you change interval.
First thing you should do with an automatic transmission is install a transmission cooler on the return line to the transmission. This drops your ATF temperature and extends the life of both the fluid and the transmission.
If you're lazy, use a good quality fully synthetic ATF and drain and fill as per your owner's manual recommendation.
If you're paranoid (like myself), drain and fill ATF every oil change, which tends to be every 10k km.
I use Amsoil Low Viscousity ATF in the Corolla.
The Swift is a Redline shop, but its gearbox.
I have no problem recommending either Amsoil or Redline.
If youre doing an aggressive change like myself, almost any fluid that meets the spec should be fine.