Hi WGB, if you ever want to establish whether your transmission is leaking, just leave the car unused for about three to four days. It is surprising how badly they can sometimes leak.
Of course, if it worries you unduly (in my case, anyway), simply degrease the box, blow it dry and go back after about four days and you'll soon see the source of the leak(s).
Modulator threads should be lightly smeared with sealant prior to fitting, so keep that in mind (you probably know that already). Another common source of oil leak can emanate trom the gear hold shaft - that seal , if leaking, can be replaced in-situ, but it's not real easy. Another source, of course, is your pan, but you have already eliminated this. Thus, I would suggest degreasing, washing and blow drying - that ought to do the trick.
Incidentally, the front pump seal, if leaking, requires removal of the box - again, I am sure you'd be aware of this. Just as a matter of interest, it is just about imperative to remove the torque converter in unit with the gearbox. If it isn't detached from the drive plate, removal could easily damage any number of components, such as the front pump bush, torque converter engagement dogs and the drive plate itself - not a smart scenario, but I am sure you'd be aware of all of that. Regards Styria