Car revs to 3000 rpm before it starts to move

I have a 1996 pontiac bonneville 3800 and
when I put it in drive and go to take off It
will rev to 3000 rpm or higher before it
takes off. It does not shift hard through any
gears, and it seems to do fine after 20 mph.
I changed tranny filter and fluid. It does
over heat because the fans don't kick on
what could make this happen I'm stuck. I
would go get a test done but can't make it
to auto shop because it will over heat