QUOTE(jijysquall @ Feb 26 2021, 12:22 PM)
Thanks for sharing your experience. I had similar symptom since my previous ATF oil change at neighbourhood workshop last year (somewhere in Feb 2020, before the first MCO) until it was resolved just recently. Looking at the old bottle that I still kept, I noticed that my previous ATF change was surprisingly using fake oil.
The symptom I had was a weird 'whirring' sound (which I suspected coming from the gearbox) when shifting from 2nd to 3rd gear at low RPM, often noticeable when I start moving from a standstill at the traffic light. Also, the gear shifting feels very sluggish and slightly jerky at that time.
I got this issue resolved recently, when I brought my TMO to AR Man Auto Care. They replaced the ATF oil, replaced the ATF filter and also put in 2 bottles of JV Auto Lube ATF treatment oil. No more sound now, and the gear shifting feels much smoother.
FYI, in between, I got the throttle body cleaned up and replaced one of the coil packs which had burnt, but the issue was still there.
To share my experience, I did encounter erratic gearshift shock which really irritates me. I was wonder whether it was due to dirty ATF fluid or whatever.
I sent to a Honda Specialist and he said try to clean the throttle body (TB) first and not replace the ATF fluid since it was replace only 8000km previously.
After cleaning the TB, reset ECU, the gearshift is a lot smoother without needing to replace ATF fluid.
I would suggest to GM2 owners to clean the TB first and see if there's improvement before replacing the ATF fluid. If still the same, then the next step will be to replace the ATF fluid.