O/D out in Cougar

i own a 93 mercury cougar with the 5.0L V8 and the other day my trans started slippin slightly in O/D and than about a week later it is almost completly gone, its there and engauges but if you give it more than 1/4 the RPM's rise and it slams into 3rd. i'm not sure wat causes this problem and was wondering if anyone could help me out. i was also wondering if the trans out of a 87 e-150 5.0L o/d would fit into my car. i have tried to find out myself but have had no luck. any help would be greatly appreciated, Thanks, Jon

Sounds like your direct clutches are shot. As far as the tranny from the van, I would be no help.