Excellent. A tranny service is much better than a tranny rebuild! Easy fixes sometimes give you the most problematic expectations. Good luck on your high RPM shifts.

You're damn right! The problem has gone, finally. The solution was transmission fluid flush. Thank you guys, especially 2GSKaizen. You were very helpful! I hope this experience will help smb else.
P.S. Use only trusted mechanics or dealerships to touch the car you love!