Cheers i was thinking as its 21 yrs old might be worth doinIt says on the sticker on the gear box "Filled for life" . General concensus is that means 100,000 miles. I changed the oil in my 2000 2.0 Z3 at approx. 60,000 miles.
https://zroadster.org/articles/how-to-change-auto-gearbox-oil.81/
I wrote this article to assist anyone else who wanted to do the same thing.
Tony.