[Huskymaniac]

Originally Posted by oab_au

First, Subaru did not design this box; it was Jatco's box that Subaru used for their application.
The holes that are drilled out larger, are the restrictor holes that have more to do with the timing of the operation of the clutches. These are used to slow the speed of engagement, to make it operate smoothly. Opening these will allow faster, but rougher operation.
An example is in the restrictor plate behind the C solenoid/transfer assemble. The restrictor holes there slow the engagement of the transfer clutch so that it does not engage with a bang, but because of it, it lets the front wheels start spinning before the clutch engages to drive the rear.

Harvey.

That makes sense. Does opening up those holes also improve flow and line pressure or does it only really increase the speed of the shifts? I was under the impression is does both. It sounds like the tradeoff was between harshness and speed (and maybe reliability).