I have the book on auto trans assembly and repair and have built a few trans myself. This book has me baffled. Flush it fill it. Check for vacum leaks if the vacum is low it will think that it is still accelerating. If you need the the book info PM me.
It can be low pressure. How are your shifts otherwise?
Happy Benzing
Darryl, Hill
350 SL4.5 #60
1967 250sl "California"