Transmission leaking problem

[Luis_gz06]

My Blazer has a transmission leaking where the speed cable adaptor goes. I replaced it with another one that i got from a junkyard. When I placed the one from the junk yard, it stopped leaking for a bit. But when i drove it around the block and came back, i parked it and rechecked it and everything was fine. 25 minutes later, i looked again and noticed a big pile of trans oil in the driveway. This time it leaks even more than with the original one. Here are some pics of the speed adaptor. Any ideas on how it could be fixed please.

Thanks, Luis.