GTR Transmission Slipping Grinding

Greetings. Based on the symptoms you've described for your 2011 Nissan GTR, specifically the check engine light, transmission indicator light, slipping gears, grinding noises, and a stored error code, there is a high probability that the issue lies within the automatic transmission, possibly the torque converter. Does the grinding noise happen in every gear, and have you noticed any changes in the car's performance, such as reduced acceleration or unusual engine behavior?

Thanks for the quick reply! The grinding noise doesn't happen in EVERY gear, mostly when it's shifting between 2nd and 3rd. I haven't really noticed any major changes in acceleration, but it does feel like the engine is working harder than it used to, especially when going uphill. Does that extra info change anything?

Acknowledging the additional information you have provided, that the grinding noise is primarily between 2nd and 3rd gear, alongside the feeling of the engine working harder than usual, indeed reinforces the high probability of a defective torque converter lock-up clutch within your GTR's automatic transmission. Given the error code stored and the symptoms, the recommended course of action would be a professional diagnostic assessment at a qualified repair workshop. Converter failure can lead to further damage if left unaddressed. I would advise against driving the car much to prevent additional problems.

Okay, thanks so much for confirming my fears, haha. I appreciate the advice! I took it to a shop, and they confirmed it's the torque converter. Repair is going to be around 2120€... ouch. But at least I know what it is and can get it fixed. Thanks again for the help!