XC90 Torque Converter Lock-Up Clutch Defect

Those symptoms do sound suspiciously like a torque converter issue, unfortunately. The grinding noises when shifting are especially concerning and point toward internal damage. When you say 'unclean gear shifts,' could you elaborate a little? Are we talking about slipping, harsh engagement, delayed shifts, or a combination of these? Knowing the specific shift behavior might help narrow things down, though a visit to a workshop seems inevitable.

Regarding the 'unclean shifts', I would describe it as primarily slipping between 3rd and 5th gear. Does this align with your suspicion of a defective torque converter lock-up clutch?

Yes, the slipping, particularly between those gears, does further support the likelihood of a torque converter lock-up clutch issue. While it's impossible to diagnose definitively online, all the signs are pointing in that direction. Considering the potential for further damage if the problem is ignored, I'd strongly recommend getting it checked by a qualified mechanic. They'll likely want to perform diagnostic tests to confirm the fault. You might be looking at a transmission repair, possibly involving replacing the torque converter. It is often the most viable method.

Thank you for confirming my suspicions. I took it to a certified workshop, and their diagnosis aligned with our discussion: a defective torque converter. The repair cost was 2120€, including parts and labour. The issue is now resolved.