Leaky 904

I have a 72 swinger with a 318 and a 904, and the tranny is leaking pretty good. I did a filter and fluid change and it still leaks. From what I can tell it is leaking from the top of the drivers side somewhere. Someone said it could be the weep hole but I did not over fill it, that I am sure of. I cant really get a good view of that part of the tranny so I can't tell where it is coming from. My brother has a 73 swinger with the same set up and his leaks from the same area, is this a common leak how do I fix it with out a rebuild or is that the only way? It leaks a puddle about the size of a soft ball or so every other day. Thanks for the info guys.