Super Custom automatic transmission fluid change

Read on another post that you should NEVER get the trans flushed/sucked, but instead drain & refill by the dipstick tube. Tried telling my mechanic mate, but he was adamant that it needed to be “sucked”, which im assuming means flushed...

Has anyone had experience of either, and what were the results?

I’ve just got myself a ‘95 SC, 1kz-te 3L turbo, so a bit old

As long as he only sucks 3 litres out it's a partial change and therefore you're fine. Draining from the sump only gets you 3 litres too.

If it comes out clean pink/red that's it, job done. If it belonged to a vicar who serviced it regularly it will be clean.

But if it comes out brown and/or smelly then change it again in 50 - 100 miles (or sooner the first time - check colour on the stick and white paper) and repeat every 100 miles until it comes out pink again.

The reason is that the new Dexron (it should say DII on the stick) cleans out the clutch face crud and you need to get it out, mine is on it's 4th change.