What rear gears are you running, and what rear gears is the governor set up for?
If they are not the same, then the Governor will need to be adjusted with new springs and/or weights to get the KD mechanism back into it's working range.
Have you installed a shift kit? With a higher pressure TP spring.? That also has to be factored in.
I have not put a shift kit in but one of the previous owners had something done to it in the 90s or 80s, I have a receipt for some transmission overhaul. But i have no idea what was done.
