2011 Juke CVT question

[Keita101]

Hi All,

I've posted about this issue in the Juke forums a few days ago with no luck. I recently bought a 2011 Nissan Juke with 55k miles. Now at 58k miles in the cold, my CVT makes a humming sound. It doesn't sound like supercharger whine, which is what the common whine sounds like when the CVT is starting to overheat. Instead it is a low-pitch humming/whining/droning sound. After the engine warms up 3-4 bars, the CVT starts making a humming sound when I hold the engine at 2500-3200 rpm. After the engine reaches full operating temperature at 5 bars and the car is driven for 10 or so minuets, the sound gets quieter. You can still hear it with the window rolled down, however. Is this just a characteristic of the CVT, or is it something I should be worried about? Has anyone else heard this noise before?

Thanks for the help.

[PapaSmurf2k3]

I don't think I've ever heard of that.
Does it still function? It should still be under warranty too, so you could always bring it back and voice your concerns with the dealership.

[Keita101]

it still functions just fine. there are no drivability issues at all. I had a drain and fill done at a dealer in town, but noticed the sound when it started getting cold. I took it into a different dealer because the dealer closest to me has kind of a shoddy service department. The fluid was about a half quart low according to the other dealer. After they topped it off, the noise was much quieter, but still there. I made an appointment with them to take another look at it next week. Hopefully I'll have a more concrete answer then.

[PapaSmurf2k3]

Cool. Keep us posted.

[lne937s]

I had another thought in this... While small displacement turbocharged engines have hotter exhaust before the turbocharger, after the energy has been extracted by the turbocharger, the exhaust is cooler. As such, the catalytic converter has a harder time getting up to temperature. One of the ways Nissan addresses this in the Juke is to adjust the transmission's ratio to slightly raise the RPM while the car is warming up. Could this be part of what you are hearing?

There may still be some noise with a normally-operating cold transmission, as the CVT has a torque converter and the fluid is not yet up to temperature. For example, wife's grandparent's automatic Toyota Corollas also make some torque converter noise on cold days, as do many automatic cars. Not loud and not abnormal, but noticeable if you are listening for it.