Vibration at low rev range - CVT?

[Robbo67]

Hi I have a 2016 ZRE182R Corolla Hatch CVT Auto.

I have an issue that is doing my head in but not sure if it is just me or if it is normal.

Firstly I've never had a CVT auto before so I realise they are a different to a normal auto. Secondly I'm a bit of a conservative driver so I don't drive it like I stole it.

The problem is that I've noticed there is a distinct vibration which seems to be from the front of the car. It seems to occur mostly when the rpm's are in the low range of between 1000-1300 rpm. It is not overly bad it is more like a drone noise sort of like the sound of deep base tone that you get from your stereo (if that makes sense?). In fact as I usually have my car stereo on I thought the noise was coming from my speakers at first but it's not. If I tap on the accelerator pedal to give it a few more rpms it goes away but as soon as the revs lower to around 1000 or just above the droning/vibration continues. Even at around 100km/h at just over 2000 rpm I can hear it.

The car has 18,000km on the clock.

Now that I am noticing it more it is becoming more annoying and I've even considered trading it in for a manual. Although the good points I have noted with the car is I'm getting 5.8L per 100km which is outstanding.

Anyway not having owned a CVT before I am wondering if this is normal or could it even be another problem not related to the CVT?  If it is not normal of course I would be worried that it might develop in to something major and costly down the track and would rather get it sorted sooner rather than later.

Thanks in advance guys and girls :)

 

[campbeam]

I had to re-read the attached URL to locate the short sentences about noise and drone.

http://www.galetoyota.com/blog/pros-and-cons-of-a-toyota-cvt-transmission/

Attached URL has an interesting comment about the longevity of the CVT in the Japanese market.

https://www.reddit.com/r/Toyota/comments/3rck0f/looking_at_a_2016_corolla_but_not_sure_about_the/

 

[Robbo67]

Thanks Campbean, interesting read :)

[campbeam]

If you do a search; you should find posts by Forum members who have got good results using sound deadening material from Jaycar.

I have noticed that the 2017 Corollas have been fitted with improved sound insulation so maybe it is something for due consideration.

[Robbo67]

Thanks for that Ashley :)

 

[Robbo67]

Thought I would reply to my own original post as I have an update and thought anyone who is facing the same situation would be able to put their mind at ease.

As the problem was doing my head in I decided to get the local Toyota dealer to assess the problem and booked an appointment with their senior technician. He is a guy specifically employed to troubleshoot any concerns owners may have with their vehicles. Before I went in I was apprehensive as in my experience often dealers will tell you there is nothing wrong and it's all in your head!

Anyway I brought the car in and thankfully straight away the technician agreed that there was a vibration. He didn't think it was CVT related though and thought it was more to do with tyres.

So I got the car serviced at the same time and when I picked it up he said the wheels were out of balance and that they balanced and rotated them and everything would be fine.

Well as soon as I drove out of the dealership it was still exactly the same.

So today I went back and confronted the tech (nicely) without an appointment and said that the problem is still there. He said I would need to book it in again for an inspection but after a brief conversation I said the problem is still doing my head but I conceded that maybe the issue was just normal and a quirk with the design of the CVT and asked if I could take a new demo Corolla to see if I can replicate the problem in that. If it is then I'll try and live with it and accept that it is normal.

So I took the demo Corolla for a drive and it was exactly the same. At low revs from 40-60kmh when the rpm drops from 2000 to around 1000-1300rpm there is a distinct vibration, rumble, drone sound and feel. So with that in mind I said I was happy that my car is not faulty and that it is just the way the CVT is in the Corolla.

I drove mine home but still annoyed I decided to switch over to "Sport" mode instead of the normal "Eco" mode. Amazingly I do not get the vibration in sport mode. I've noticed that in sport mode it seems to keep the revs up in a much higher range. At 60kmh in sport mode it hovers around 1800-1900rpm and no vibration. When I flick the switch back to Eco or normal mode the revs immediately drop to around 1000-1300rpm and the rumble reappears.

So the sport mode basically cranks up the RPMs higher for slightly more power. The noise only happens while in normal eco  mode - never in Sport. So in my opinion the CVT is "underloading the engine" which causes the vibration at low speeds; basically the CVT's computer is trying to match a good rpm ratio for my low speeds and it sometimes can't match it. So it's not a problem and my engine/transmission is perfectly fine.

So in conclusion I am happy to switch it to sport mode so that the annoying drone/rumble/vibration is not present. I think around town I'll keep it in sport mode and highway driving switch to normal. Happy to compromise a little on what will probably be a little bit higher fuel consumption but other than trading it in for a manual or conventional auto and losing money I'm happy enough now to continue around town in sport mode. :)