Hey Fredness, great question!
Here's the scoop - you MUST replace the Separator plate to transmission gasket everytime you drop the VB.
If you use a bonded separator plate, some of the adhesive releases from the ATF and temps, the PAPER gasket lifts from the plate causing issues. The overall dimensions of the gasket itself changes enough to cause issues with your torquing - the gasket actually bunches up at the bolt, laying over itself.
Pix to follow - they are pretty dramatic.
There was a pathway in the TCC area that lifted 1/8” (or more) and actually ruptured at the end – I believe this was a result of poor torque from the bunched gasket.
Lesson learned, replace the gasket each time.
Now, why don’t I say “replace the separator plate and bonded gaskets each time”? I’m glad you asked! I would lose at least 5 modifications to the separator plate, to include:
One TCC port closed off – EPC overboost fix from Ford.
OD apply/4th gear engagement boost (Sonnax/CVB).
TCC exhaust hole enlargement (reduce TCC slip and code P0741).
Direct Clutch and Servo Release Feed hole enlargement.
EPC solenoid feed enlargement.
Pressure Regulator balance orifice enlargement.
Line pressure to converter feed orifice enlargement.
So, basically, if you have a Sonnax/CVB or Ford EPC correction kit, you will have TCC issues and lose up to 5 mods. If you replace the bonded separator plate, you will have to re-do the TCC block off at a minimum.