need help! why in the hell is my transmission leaking around the right axle stub???

[fliped wrx]

i recently just bought a rebuilt 04 transmission and made it fit with my 05 wrx but when i had put it in after a couple of days later..i found drips of oil on the ground and it wasn't motor oil it was gear oil by the smell of that olive smell..well since am a risk taker i just left it alone thinking it would go away and now it has gotten worse! so i went underneath the car and check it and oil was oozing from my right side of the tranny around my axle stub which is i believe the screw on thingy with the 20-30 star lug design.."i guess the seal?" could this be the problem or should i just take it back to the dealer to have it checked am already running low on gear oil or actually dry and gears are starting to feel a lil notchy kind of hard to get out of in the morning.. anyone help me out?? thanks
kevin