Please Help!! 1997 Ford Transmission?

i have a problem with a 1997 ford f150 transmission. 4.6 4x4 4sd auto w/elec overdrive eo4d. redline synthetic & inline filter 87k. just started to leak 4-5oz out of the bell housing inspection hole but the oil is not being slung by the torqe converter/flex plate i.e. not from the front main oil seal. i have the out and the seal is perfect. could it be a cracked case or the seal between the oil pump and the housing??? It mainly leaks while its sitting. Please help me!! Thanks!!