why is the transmission fluid leaking from my car on 1999 Ford Taurus

my car started slowing down while I was driving two weeks ago after the check engine light came on . I checked all fluids and transmission fluid was low .I added one bottle of fluid ,but light stayed on, fluid leaked out even after three more bottles and light is still on.

Asked by for the 1999 Ford Taurus
could be several reasons poss trans pan gasket. seek insp and est