You cannot "change" the ATF fluid without an ATF fluid exchange machine.
Then you would also want to replace the internal filter, gasket, and one time use bolts and wipe the pan clean and inspect the magnetic plug.
http://www.bgprod.com and
http://www.bgfindashop.com may help.
SnapOn also has a Sun fluid exchange machine.
Download a manual at
http://www.phatg20.net and get the TSB later.
You need to do a lot of reading here, so dig in.