Sorry to steal the thread (this may still help you). When I switched my transmission oil I had fluid come out of the breather at the top of the transmission, well I think its breathers, they are u-shaped and at the top of the transmission near where it connects to the engine. I filled the transmission though the filler hole underneath the car (not the shifter) and it still came out. It never really leaked too much on the ground as most of it just went all over the transmission. I have seen some gtr transmissions with hoses coming out of the u-shaped piece (90% sure they are breathers), so in that case the fluid would end up on the floor instead of the transmission. I also had a messed up shift boot which caused some fluid to leak. There is two shift boots, well actually 3, but two rubber ones. You first take off the shift knob in the car, then the leather shift boot, then you'll see a rubber boot with 4 screws, take that off, then you'll see another shift boot, that one tends to crack (from what I'm told). You can get it at any nissan dealer and its pretty cheap. If not PM me I have an extra.