+1.....I would guess either a vacuum leak or low fluid level..Most likely it's not getting vacuum..These automatics are vacuum modulated. Check the vacuum line. It is a hard line from the transmission up to the back of the manifold, then a short rubber piece to connect it to the manifold. Check that rubber piece.
My '67 drove great forever and then started shifting late and hard suddenly. I topped off the fluid to no change, then I discovered that my vacuum line had a nice 3" split in it. Replaced it and all was well.
And the transmission lived happily ever after.
thanks! there is a line there, but its metal and screws in. but it heads down towards the trani so i guess ill jack it up?Take off the air cleaner and look at the back of the manifold. The line will come off a fitting and run down the back of the engine toward the transmission, I believe on the passenger side.