Street, you are talking about the shipping plug. Doug once told me that you could shove the tail shaft in behind this thing and just push it on into the housing. or you can pull it out. I choose to pull this out and save it for when you need to pull the tranny without draining it .. as I have done no fewer than 6 times
Anyway, grab it with a strong pair of pliers and wiggle it out, put it in a baggie with the speedo hole plug.
Clois, steal away! But you are talking about the dust seal, which surrounds this plug and correct, you do not want to pull that off.
Sam
P.S. If you are using an electric speedo, then you will need to get the correct metal and o-ring plug from Tremec for the speedo hole. The rubber shipping plug is not meant for road use.