The only way to be 100% sure is to plug a pressure gauge into the govenor pressure tap at the rear of the case. (see the photo in Tom Hand's book page 39) At stand still govenor pressure should be 0 psi, steadily increasing as speed rises. I had a 68 Charger owner come to me with exactly the same fault about 2 years ago. His transmission had been in storage for 5 years without any fluid. There were 2 check balls in the VB that had been put in the wrong places, but it turned out that it was a stuck 1-2 shift valve. Dont forget the photos once you get the VB seperated Jeff!