Hello guys im new here, so i have mitsubishi pajero sport dakar 4n15 engine code and 8 speed automatic transmission, years 2017, 58800 KM, so the problem is, When I drive normally 50/60 Kmh or more, the rpm is normal and stable around 1.500 - 2000 rpm, then suddenly I have to lower the speed, such as braking or letting go the pedal, basically from normal/high speed then suddenly have to go low speed, then my foot automatically releases the gas pedal and moves to the brake or doesn't press the brake at all, then the rpm is drop slowly to 1000rpm, that's when rpm drop to 1000rpm i hear a "dug" or clunking noise in the outside driver's area, more like in the front of gas pedal, the sound can be heard inside the cabin near the gas pedal (right side driver). I have checked the transmission just by test drive with expert mechanic, then check the engine mounting, all bushing even ball joint and all still normal and thight, even the bolt was thight too. But If I drive at high speed for example 100kmh or more and then have to brake until I stop or the rpm drop fast, there is no dug/clunking noise. Maybe the failing of torque converter? Or the automatic transmission need to overhaul? I'm frustrated because I've gone to 10 workshops but they couldn't diagnose my complaint. Please help im begging u all because this car was the first car gift from my father.