S40 Automatic Transmission Slipping

Sounds frustrating! I had a similar issue with my old Renault Megane, though not as severe. My symptoms were mostly the slipping and the occasional clunk when shifting. Did you notice if it happens more when the engine is cold, or after it's warmed up? Also, does it seem to be worse at certain speeds or gears?

That's insightful, thank you. The symptoms appear irrespective of engine temperature, both during initial cold starts and after prolonged operation. The slippage seems more pronounced at lower speeds, particularly during the transition between first and second gear. What was the resolution for your Renault Megane?

Unfortunately, my issue wasn't something I could fix myself. I ended up taking it to a transmission specialist, and they confirmed it was a torque converter issue, just like you suspect. Considering the grinding noises you're hearing, it sounds like yours might be further along than mine was. Honestly, I'd recommend getting it checked out by a reputable workshop ASAP. Continuing to drive it could cause even more damage.

Your insights are appreciated. A trusted mechanic confirmed the diagnosis of a defective automatic transmission converter. The repair, including parts and labor, cost 2120€. Thank you again for your invaluable assistance.