The fill port is on the right side (passengers side) on the trackick 5 speeds. So I am not sure what you are calling the fill port.
There is a rubber plug that is supposed to be in place between the backup and 5th gear switchs (actually yours probably just has the backup switch), on the drivers side of the tranny, up high. If that plug is missing, gear oil can leak out. I am not sure how much will leak out, since I haven't ever ran without one, but it is a passage into the tranny, so some can/will leak out.
It isn't likely that gear oil is leaking out between the shift tower and the tranny. For one, it is on top of the tranny, so it would be pretty hard for gear oil to get slung that high, then actually leak out.
Are you sure it is gear oil and not engine oil? If the oil pan is leaking, then it can blow back all over the tranny/cat/etc. and be hard to tell from where exactly it is leaking.