Gary50

Hi guys,

I brought my 2002 sc430 to a private mechanic for suspension work, it works fine (Engine, Transmission, etc.) before I gave the car to him (Engine lights and VSC on). But the car works strange when I got it back: idle rpm is about 1100 rpm in N (Warmed), when the car is in gear, and coming to a stop, it will stay at 900rpm for a couple of seconds then drop to ~650 rpm which I believe is the normal rpm but it has noticeable vibration.

I talked to the mechanic, he said he filled some OEM transmission fluid into the transmission because he checked the fluid level is low. But I checked the fluid level that is actually about a quarter-inch high when it is running and warm. I doubt he overfilled the transmission.

My question is: Does overfill transmission fluid cause this kind of situation? Or it's the problem of the OEM transmission fluid?