I changed the rear transmission fluid at 60k KM.
Used the original Toyota ATF WS oil as per Lexus owner's manual.
Since that I experience a strange short scroop sound coming from rear irregularly - only at the moment I press the gas pedal to accelerate the car, but not every time.
The level of fluid was checked OK few times after the change, there was no need to refill.
Any clue what could be the reason ?