So, I replaced all the lines, transmission to radiators.
It all went smooth enough (I noticed one of the lines up front slightly bent)
So now the transmission behaves different, I checked the level a million times, cold, after all gears back to N, etc. done this before many times before, so I am very confident it is on the right level (and it was the same before).
So anyway, the box now feels like a new box, it shifts later, but engages harder (not bumpy, just you can feel it shifting more), it shifts later too (before it would shift in the 2-2.5K RPM, now it seems to go 2.5-3K RPM). The torque lock seems to engage as always in the 50+ MPH and it goes very smooth and strong on freeway, going up or down small grades. It seems to keep the whole thing cooler too (which I could understand since the old lines were, well, old and leaky).
The new lines don't leak (AFAIK) and there is nothing weird, again, AFAIK, but just replacing the lines and adding whatever ATF it lost (which came out clean enough and it is the left over from my last ATF filter & fluid change) shouldn't make a big difference.
Or should it? Maybe the old line were not able to keep the right pressure or the new ones are bad? (This is a kit from Atlantic British BTW)
Your opinion appreciated.