[Crazy_pilot]

Regarding the valve body holes, my feeling is that they were unprepared for how theory and reality seldom mesh as one expects. It's possible that on paper the valve body had sufficient flow, but in reality that flow is restricted by debris build up or some other interference. Maybe Subaru rushed the 4EAT into production too quickly and short-cut the durability testing.

I don't drive my SVX in the winter anymore, but it always took a good while to warm up to the point of T/C lock, to the point that I didn't like getting on the highway too soon and winding it up to 3000 RPM to keep up with traffic. With an external cooler I think you'd want to have a block-off plate for winter driving.

Actually, now that I think about it, I've driven my car on days so cold that the transmission would unlock every 10-15 minutes on the highway to re-heat itself. Obviously in cold weather the 4EAT doesn't have heat issues.

I think the ultimate solution would be to have a thermostat controlled external cooler. I would like to see the trans fluid running through a warming circuit during the initial part of driving to get quicker lock up and better mileage, then switching to a cooling circuit as required to maintain the minimum lock up temperature.