If you've done a lot of hard km's on your auto, don't just flush it, replace the pickup screen.
There is at least one driver on fjcc (FJ runs the same auto) who burnt his oil and clogged the pickup screen with broken down colloidal muck, and starved the torque converter. $3000 replacement.
The pickup screens are cheap from Repco, you can even get oem through Dubai Amayama for around $50. Toyota parts in Australia will charge you around $200 for the pickup screen and the filter.
Penrite advise not to get WS or LV over 100C. If you're hitting those temperatures, you'll need to consider a larger cooler.