After putting the plugs (drain- & check-plug) back on and filling about 5L of new ATF Fuchs Titan 4400 into the transmission, I was ready for the next phase: Letting a little helper start the engine very briefly - initially to confirm that the ATF would come out of the pipe, where I expected it - it did not, which is why I placed just pipes over everything to avoid a mess. As it turned out, the ATF came out by the green garden-hose, i.e. the upper pipe was the one coming FROM the transmission.NN