Grinding CVT gearbox

A

Ashton

Hi all,

I am new here so massive apologies if I have posted this in the wrong place.
I bought my wife a 1998 R reg Micra K11 auto for her to learn in. She has her test booked for 21st September but over the past couple of weeks the car has developed an issue. During engine braking or slowing down, when the CVT box drops speed (I know it's not dropping gear as such), during this varying of speed, there is a noticeable grinding noise that you hear & feel. The car generally drives OK & there is no N-CVT warning light or anything but if nothing else it will be disconcerting for the driving test examiner, especially since it is more noticeable with the radio off...

I was thinking it could be the transmission fluid that needs renewing or perhaps from reading, the electromagnetic powder brushes of the clutch system that need renewing...

Any thoughts on this would be appreciated.

Ash
 
Change the oil and see what happens bud. Could be a few things, hopefully its the oil.
Maybe to low, or to much in there, that doesn't help. See if the oil is burnt or not, that's an indicator of problems.
 
Hello
How low does the speed go before it does it?
On our 1998 CVT, when the speed drops very low (such as moving slowly when parking or maneuvering on a car park), ours makes a slight but noticeable grinding noise. I had this checked out at the Nissan dealer when we bought it 12 years ago & it was said to be fine. I always assumed it was something to do with the powder clutch & the iron filings within it effectively slipping due to the low speed.
Hope all is ok with yours.
Dave
 
Hi Dave,

Fluid changed & no real difference. Like your Micra, the noticeable grind is around the drop into the 10mph zone, e.g. if I accelerate along (past 10mph) then let it roll, it will grind when it drops back down to around 10mph. I know CVT doesn't select a cog per-Se but whatever it does to adjust to a lower variation seem to be where it grinds.

I am thinking it could be the powder clutch. Generally I dont care too much as it drives fine, it's just my wife has her test in it on 21st & I would hate for the examiner to either A. Think it's her poor control, B. Abruptly stop the test due to fearing for his/her safety!!

Will you bother getting yours looked at? Cheers.

Ash
 
Hello Ash
Ours has been doing it for 12 years now, so I think i'll just leave it alone ;)
Like I say, the Nissan dealer said it was normal & it hasn't gone bang yet (I'm touching wood as I say that). The noise ours makes does sound like powder grinding, so I've always thought it's the powder having to slip due to very low speed. I'm no expert though (lots of the guys on here know these little cars inside out so they'll know more).
I really can't see the Test examiner bothering to be honest. If he mentions it just get your Mrs to tell him it's the powder clutch in the CVT gearbox - he'll probably be impressed at her car knowledge - he won't know if it's correct or not :D
Good luck to your wife, great choice of car to learn in.
Dave
 
Reviving a dead af thread but mine is doing this. No lights on, brand new fluid and filter as of last week, brushes still have life on them. However.. Get down around 10 - 15 mph and ya get a nasty shudder and thud when the clutch does its thing. I'm thinking its the clutch but not certain, and not only being in the US but having a Japanese market March of which there are 5 in the country... Makes parts very hard to find and no shop will touch it without charging a really stupid amount. I am worried about breaking the gearbox if I drive it any longer.
 
Just to say mine has been doing this for a while, when dropping down to the sub 10mph zone, I am assuming it to be dropping down on to the lower cog (the one which DS gearbox used for), as when driving off from standstill after 10 mph feels like it's changes gear up.
I have never let this worry me even though it does sound terrible. I just continue driving my K11 until gearbox says now more, as to get the gearbox taken apart etc be more than the car is worth!
 
Ashton said:
Hi all,

I am new here so massive apologies if I have posted this in the wrong place.
I bought my wife a 1998 R reg Micra K11 auto for her to learn in. She has her test booked for 21st September but over the past couple of weeks the car has developed an issue. During engine braking or slowing down, when the CVT box drops speed (I know it's not dropping gear as such), during this varying of speed, there is a noticeable grinding noise that you hear & feel. The car generally drives OK & there is no N-CVT warning light or anything but if nothing else it will be disconcerting for the driving test examiner, especially since it is more noticeable with the radio off...

I was thinking it could be the transmission fluid that needs renewing or perhaps from reading, the electromagnetic powder brushes of the clutch system that need renewing...

Any thoughts on this would be appreciated.

Ash
Click to expand...
quick fix: Don’t buy CVT’s
 
Yup mine has done this since i got it, never been an issue even with fluid changes, part of the car now. Auto only license has ensured I have two spare N-CVT's in my kitchen under a plastic blanket, which ain't for sale unless I part with the car. :)
 
5949403030495959 said:
Yup mine has done this since i got it, never been an issue even with fluid changes, part of the car now. Auto only license has ensured I have two spare N-CVT's in my kitchen under a plastic blanket, which ain't for sale unless I part with the car. :)
Click to expand...
Did you ever sell it? If so, let me buy one of your spares haha. I can't find one anywhere.
 
There's no lower cog, the cvt slips the EM clutch below 20km/h or so depending on the situation (it's in the manual somewhere).
Don't have the toque converter model so I can't speak on that.

Best guess is contamination in the clutch, also be sure to use normal ATF not CVT fluid.
 
Last edited:

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