BXProject

I think "shitbox" design flaws are just part of modern motoring.

Like this Vectra, they decided to run the ATF cooler for the autobox through the radiator internally and they have a nasty habit of corroding the cooler allowing the coolant into the box and writing it off! Just spent £80 on 5 ltrs of ATF to give it a change and check the condition.

Why can't we go back to smog producing tractors?!

Not had much experience of modern slushers. The Manta I had was a special, with the fore runner of the more modern sequencial box.
What it had in common with the full auto box was a hydraulic valve block in the sump.
If they still have these Jay, it was always policy to use a flushing agent, (STP used to do one), as they do get full of sludge and shit, before refilling.