Full Race 904 D/2 Problems
I also have no governor any more - it's replaced by an aluminum spacer.
To me, your issue DOES sound governor related since the governor is sort of like a mechanical road speed sensor. If it's 'hunting' like you say, perhaps it's not seeing what it's supposed to see in terms of pressure to make the shift. Did you eliminate the governor before you rebuilt the trans or after?
If you have no governor, I'm not sure if/how it would affect the line pressure but we would probably presume that it does. Maybe Tracy or someone with a little more knowledge can answer that.
So then, with the VB modified to reroute said governor pressure to provide constant full line pressure... well, I think your answer might be in there somewhere. Whether it's directly related to those parts or not is the question. There may be an adjustment somewhere or some sort of provision you need to add to handle or compensate for the modifications. Maybe you need a check ball or plug somewhere, different manual valve... something.
Read what Kunkel says in the reply about how the TF3 is modified. Also, did you see the part about the plug in the case? Do you have that plug?
"...The way the TF-3 makes the valve body full manual is to reroute the governor circuits so that the governor pressure circuit always has full line pressure, this way the trans will shift to the selected gear regardless of car speed. If the port in the back of the case that leads to the governor is left open, the governor pressure can bleed off through it. See the diagram below, the governor pressure port is where the soft plug is supposed to be installed.
Because the fluid routing for the gears is the same as stock, the rear band will apply in 1st and should supply compression braking; reverse pattern manual VB's usually don't apply the rear band so there is no compression braking, it just freewheels when throttling back in 1st.."
