Leaking transmission fluid

[esandes]

Well, I went to look under my car where I left a couple of sheets of cardboard under the engine as it is in storage and I wanted to know if it was leaking anything. Sure enough, the cardboard is soaked with transmission fluid. I had my parts installed (in my sig) the shop said the seal where the driveshaft mates up with the transmission is slowly leaking. That was a surprise since my car has never leaked before. So they charged me for the new seal and labour.

Is this a common thing for the tranny fluid to leak there? I guess it's not a good idea to just drive the car 1 block away to a shop where this can be fixed.

What are the do's and don'ts for a transmission that has no fluid? I'd better top it off before I drive it to the shop.