I'm a Transmission/BT newbie, but I've spent a fair amount of time in a good faith effort in the FAQs etc trying to solve this issue without luck.
Transmission 1.54 on Mac OS X 10.4
I've got the TCP and UDP ports opened in my OS X firewall
I've got my ISP's router doing an IP passthrough to my machine
The green "successful mapping" ball shows up in Transmission settings
I can download files with no problems whatsoever
The problem is that seeding doesn't appear to be working. When I first start Transmission up, the files I'm trying to seed show 1 or 2 peers but no bytes uploading, then quickly drop back to zero. It's happening with a couple of files that downloaded pretty fast so I suspect there are others trying to get them. Any ideas?