Well noises are hard to pinpoint so do my video finding the sources of car noises Scotty. Then go from there if it is the transmission whistling pray that it is the vent that's clogged up and it could whistle air and not internal wear that is whistling because gears are bearings are worn

With Nissan Jukes 9/10 times it’s Pulley bearings - a very common sign that your transmission is about to go bad on Nissan/Renault/Mitsubishi/ older Toyota CVTs.

it’s typical to see it at 100k-120k miles.

try to replace the fluid, it that won’t help - it’s going to get very expensive real quick.

I’d replace the fluid anyway, and just pray that it’s some other bearing that might be causing the sounds.

There’s technical service bulletin on what seems to be the RE0F10 transmission, and as far as I know your one has a RE0F11 - but those are breakdown more frequently with this exact issue.

Try to locate a TSB for your car, here’s one for Altima/Route models that are experiencing the issue your described:

https://static.nhtsa.gov/odi/tsbs/2018/MC-10141438-9999.pdf

(^ BEARING WHINE DIAGNOSIS)

unless you are covered by a warranty extension, or know a good CVT shop - it’s not going to be economical.

but if you do, this is the repair you’d usually need to do:

https://static.nhtsa.gov/odi/tsbs/2018/MC-10152011-9999.pdf

(^ CVT BEARING REPLACEMENT)

That’s an involved 131 page procedure, not something most shops used to working on regular automatics can do IMO

Sell it anyway and get something with a regular automatic - I don’t care if it’s a Nissan, Scion, Honda or a Toyota, CVTs are a total nightmare no matter who built them (some are less Toyota K120 seem to be worse than Autos but not terrible, some like Toyota K313 are junk) Only conventional torque converted automatics and manuals hold up over time.