Thanks for the insight . I went to a couple of workshop , 1 suspect is electronic board . The other quite sure is ecu.
Did atf oil change . Atf filter also changed . Same issue but getting worse as the months went by . Now almost everyday when stationary , change gear from n to d, car also slight jerk
Instead of trying luck , most likely will go to Komoco solve once and for all
I hope we are talking the same symptom:-
1. At stationary, it hesitate to change gear.
For me, when I shift from P->R, there is a delay before it engaged.
Also delay in N->D.
This is definitely solenoid problem.
2. Kicking / knocking when engaging D --> R.
This happens when I want to reverse into parking lot.
Shift from D->R like immediately after car fully stopped will sometimes give a violent knock.
If I wait for 2-3 seconds after full stop and shift, it's OK. So I am practicing this now.
3. Kicking / knocking during highspeed downshift from 4->3.
Usually happens after cruising for long time on 4th,
then floor accelerator to pick up speed for overtaking.
My workshop also noticed (1) and (2) above when they move my car around during servicing. They gave me feedback about it, but since they are not gearbox specialist which they openly tell all their customer, they didn't offer repair advise.
What I had done so far:
a. On receiving the car (127,000km on clock, genuine) --> Replace ATF and filter.
b. At 135,000km, feeling all above symptom --> Replace ATF + 1 bottle additive / cleaner.
c. At 148,000km, after plentiful of instigating the kicking of gearbox (to get the solenoid work hard with cleaner) --> Replace the ATF.
The symptom is very much relieved and gear change is very smooth now. Still get the knock but it's rare now, and it's very mild knock for (3) above.
To reduce cost, I bought Hyundai ATF from Malaysia HyunKia or Mobis stockist for RM85 / 4 liter pack. The additive / cleaner cost me RM35. I still have a bottle of additive in my trunk, with 2 pack of ATF. If you keen to try, I can always pass to you.
To me, it's no harm trying the additive with the intention of overhaul the gearbox if all doesn't go well. Going back to Komoco for a solenoid problem, means changing the entire valve body, if they do that at all. No harm asking though. However, I am ear marking workshops that does gearbox reconditioning in case I need to drop it there for such a job. Will compare to cost of replacing valve body at Komoco.
BTW, my ride is i30cw but it has the same engine / gearbox / mechanical as the Avante.