[russellw]

Yes there is a drain plug (see pic below). Always replace the drain plug seal when refitting.

Once drained and the plug replaced the trans is refilled via the fluid level indicator (dipstick to us).

Expect to use about 5.75 litres to fill the system - recommended specification is WSS-M2C924-A (e.g Mobil 3309 ATF) and the total you'll need will depend on how many cycles you want to flush with.

If you are concerned about potential failure, use a paper filter when draining and see what it collects. Some small metal particles are normal.

Cheers
Russ