Mine one KO after 2 to 3 packs of battery. It is not 掃左 but the base of the large gear broke and it become two pieces. I am sure it won't happen if it is metal gear. I am using HW 120A + 3000 kV + 300000 diff oil. Maybe the 300000 oil is too sticky and the plastic gear cannot withstand the force.
My friend's one also KO (掃左) after 2 to 3 packs of battery. He is using 13.5T + 300000 diff oil.