Agree with this post but I think improved flow speeds up the shift.
One of the features I liked about the griner and tranzact brakes
Is that they remove all the shift valves and unnecessary fluid passages. The billet bottom half has the fluid passages enlarged
and shortened to speed up the shifts. The use of an accumulator is eliminated completely. But I agree it is the pressure that does the clamping. The reason that I drilled and enlarged the passage to the hig gear clutch is that I noticed on my pump that this passage size becomes the limiting restriction size in the flow bath. This passage is huge in the billet valve body to speed the transbrake release, the common modification between the sealing rings also improves the flow. But the size of the drilled passage in the pump itself remains smaller than both of these on the 904, so I opened it up as well.
Also where the two pump halves bolt together, the flow path has square corners, so I rounded those to assist flow to high gear.
