D16Y7 auto tranny with 240k miles is being weird.
Tranny would shift mildly hard through most gears.
The fluid was in awful condition so I changed it, just once, not a whole flush tho. It shifted better for a while, now it's back to doing the same thing.
There was no metal in the fluid, normal amounts on the magnet.
It shifts totally smooth from 1-2 all the time, but mildly hard for the rest of the gears. Occasionally shifts will be very slightly delayed at low rpms, I could be mistaken though. Sometimes when I'm flooring it in 3rd it will straight up refuse to shift and trigger a temp cel before shifting and acting like nothing happened. If I lift it'll shift no problem.
Other than that everything's great. It doesn't slip, grind, whine, or make weird noises at all really.
It's my daily so I'd really like to get it figured out. I suspect that I need to get all the old fluid out or replace a solenoid. It's nothing very concerning to me it's just really freaking annoying. If I drive like a grandma the car behaves just fine.

 

You can try the 3x3 fluid "flush". What that is, is drain 3 liters and refill with 3 liters. Drive 100 KM, then do it again, drain 3 liters and fill with 3 liters. Then drive another 100 KM. Then do it a 3rd time, drain 3 liters and fill with 3 liters and your tranny is considered flushed.

If this doesn't change the behavior, then the damage is already done and your transmission is just worn beyond just a fluid change.

 

I'll definitely try that with genuine Honda atf instead of pure synthetic Valvoline. Hopefully it'll help.
However I'm not inclined to think if it doesn't that my transmission is shot. The behavior doesn't line up with a bad trans. According to my research it's rather common for the linear solenoid to go bad and cause identical issues to mine. I suspect that's the real problem.