2018 Infiniti QX60 POWER TRAIN,UNKNOWN OR OTHER,ENGINE

The rear differential is messed up on this truck, and there is grinding noise - when i turn left or right, and there,s a whinning noise while driving, and also black fluid drips from in between the oil pan, and transmission and hissing sound when turned on..

I purchased my 2018 QX60 in 2021 at Competition Infiniti as a certified pre-own vehicle. I soon began to hear a rattling noise and the steering wheel would vibrate a little. I brought the vehicle back to the dealer several times with this complain and they keep telling me that their is nothing that the can do for me because that’s the way the vehicle is built. The noise as I was told is common in QX60 models and that I’m not the only person that has complained about it. I told him that I don’t expect for a $30,000+ Luxury vehicle to sound that. They also explained to me that it was something that was built in the vehicle to help with fuel efficiency. I think he called it a Droner or something like that. I love the look my vehicle but I hate driving my vehicle because of this noise. I filed a complaint with Infiniti consumer service as well, who instruct me to have the fail inspected by another Infiniti dealer to make sure the dealer is not refusing to fix the problem. I am disgusted that a vehicle that I purchased at an Infiniti dealer is sounding like this. If you can provide any help in this matter, it would be greatly appreciated.