i hope you dont have the tranny lines Looped..If so this is One Big problem for over heating..outside what the others said..you may want to try some Hydraulic Fluid they say it runs cooler.
just out of curiosity you wouldn't be running to loose of a conveter would you ?...running a looser converter than what you need will also make that tranny heat up more......
just replaced a buddy of mine tranny ( 350 turbo ) for running to soft of a converter on the street..took his tranny right out..
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Bjuice..
"I'M YOUR HUCKLEBERRY ! "