iQ Automatic Transmission Converter Defect

Grinding noises aren't good, are they? Slipping gears and warning lights point to transmission trouble, that’s for sure. Has the transmission fluid been checked recently, and what condition was it in? Does the grinding happen in all gears, or only some? It really does sound like the torque converter, but have you considered valve body issues? Either way, this sounds like a complex one.

The transmission fluid was inspected during the last service and appeared normal. The grinding noise is intermittent and seems more pronounced in the lower gears. Regarding your question about valve body issues, could you elaborate on how a valve body malfunction might manifest similarly to a torque converter problem? What are your thoughts on the error code that was logged?

Normal fluid is reassuring, but intermittent grinding still suggests internal wear. And as for the error code, that could provide more clues. Yes, a faulty valve body can definitely mimic torque converter issues because it controls the fluid pressure and flow to the various clutches and bands in the transmission. If the valve body is sticking or malfunctioning, it can cause erratic shifting and slipping. But all the symptoms point towards the transmission itself. The grinding, especially, isn't something you want to ignore. My advice? Head to a reputable workshop, they'll be able to diagnose this more accurately. A proper diagnostic scan can pinpoint the problem.

I appreciate the detailed explanation and advice. I took the car to a reputable workshop, as you suggested. Following their diagnosis, they confirmed the automatic transmission converter was indeed defective. The repair cost came to 2120€.