Hey,
The leaking seems to have stopped after I used the pliers (not too tight
)
However I've been to a transmission shop today, and the guy told us, that the problem caused wasn't actualy by the transmission, but by "misfiring under load". In the end it was just a bad lead, and the spark plugs were also quite old...
But anyway the fluid was extremly low because of the dripping, and I'm glad I have that sorted out now... Hopefully no more serious problems (though there are some more minor ones, but that's for next time
)
Thanks a lot for all the answers, it's always cheering me up to read some of the comments
Ah and by the way I really enjoy driving in Australia with our beautiful commodore
(although I sometimes think, that this massive 3,8L-engine is a little bit of a waste with all the speed limits here compared to the German Autobahn *making-everybody-jealous* XD - sorry guys
)