Jerky CVT

[Pumpkin]

I only bought my Jazz in February and the gearbox is noticeably jerky now. It can mostly be felt when braking and letting off the brakes, pressing the accelerator again results in a kick. Even just letting off the power and then back on it again can produce the kick feeling. When pulling away it sometimes does it too.

Any ideas on what this could be? I saw very similar symptoms for starter clutch issues but not sure if mine (2012 es) has this.

Thanks.

[VicW]

The 2011 facelift models and onwards have torque converter clutches.
Oil change intervals for the CVT gearbox have been the subject of some discussion and regardless of what the handbook says an oil change interval of 25,000 miles or two years seems to be the current recommendation by Honda. I checked with my Honda dealer and that was their figure.
When was the oil last changed, do you know, this could be a good place to start?
If bought from a Honda dealer it is still under warranty so that should be your first port of call.

Vic.

[Pumpkin]

Yes, it was an approved used car and is under warranty. I'm not sure the oil has ever been changed, and I am aware of the confusion over oil change intervals. How would I know if it had been done? By asking the dealer to look at their service records?

[VicW]

There is a space in the service record book for transmission oil changes to be recorded plus the dealer should have it on record if they sold the car originally.

Vic.

[chrisv]

Hi,
Any problems with the dealer arguing about oil change intervals I can send you my email from honda with the definitive answer,
Regards,
Chris
PS
When you pull away if you wait a moment after releasing the brakes you will feel the drive engage and be able to pull away smoothly, otherwise there can be a slight jerk, also when you slow down on the brakes as you come to a halt the car seems to change into low gear, I don't worry about it

[mattl369]

What you are describing is, I think, the same issue I am having. I have done much research into this and spoken to Honda about it and have been told it's normal. I have driven 2 other Jazz CVTs and they both did it to a greater or lesser extent.

Basically, the torque converter in the CVT has a slightly different role than other automatics. Basically it is there just to get the car rolling. This is where most clutch wear occurs. At about 15mph, a lock up clutch engages. When accelerating, you'll notice the revs drop slightly at this speed - it feels like a normal auto changing gear. It's the lockup clutch engaging and taking out the inefficiency of the torque converter - the differential between the drive and driven side. The jerk you feel when slowing down at about 8 mph is the clutch disengaging because the other parameters for it disengaging at a higher speed have not been met. Lock up clutches on traditional automatics engage/disengage at higher speeds. Unfortunately, in this cvt the lockup clutch is sometimes engaged at lower speeds. If you stab the throttle at low speeds, it will suddenly disengage and cause a jerk. Sometimes if you accelerate and then quickly release the throttle, it remains locked up for a second and then releases which causes a jerk. I seem to be the only person who has driven my car that has noticed this. I also don't notice when a passenger. Mine is due a fuid change so this may help a bit.

I have managed to adjust my driving to limit this. Gradual press or release of the accelerator (rather than a prod) helps. In traffic, putting it into S mode also helps.

The jerk when you release the brake and accelerate from stop is caused by the rollers engaging the steel belt. It depends how hard you press the brake at a standstill. If pressed hard, the steel belt will be released, effectively putting the car in neutral. Release the break and it will need to engage the steel belt. If you press the accelerator before this is complete it will cause a jerk. The best way to avoid this is lighter pressure on the brake at a standstill so it doesn't release the belt, release the brake slowly or release the brake and wait a second or two.

Hope that answers the question!

[Pumpkin]

You've perfectly explained the issues I'm having, well done!

[olduser1]

I would give the dealer a letter stating your Jazz has had an issue with the CVT, ask themn to put it right, just suggest they start with repalcing the fluid. Its their issue to reslove, good luck.

[Pumpkin]

Hi,
Any problems with the dealer arguing about oil change intervals I can send you my email from honda with the definitive answer,
Regards,
Chris
PS
When you pull away if you wait a moment after releasing the brakes you will feel the drive engage and be able to pull away smoothly, otherwise there can be a slight jerk, also when you slow down on the brakes as you come to a halt the car seems to change into low gear, I don't worry about it

Chris, can I take you up on that offer of sending me the email from Honda? The car is going into the dealership on Friday to be checked over. It hasn't had its CVT fluid changed yet at four years old.

I appreciate Chris might not see this post, I can't contact him from his profile.

[chrisv]

Hi,
If you send me your email by personal message i can forward the correspondance to you,
Chris

[mattl369]

I've had the CVT fluid changed. It makes no difference. Unfortunately its a software thing - to preserve as much economy as possible, it keeps the torque converter locked up as much as possible which causes a less smooth drive. Honda UK have said there's no update to 'fix' this.

By putting it in s mode, none of these irritating things happen. It doesn't go into neutral when stopped and it locks/unlocks the torque converter at higher speeds where it is much less noticeable.

[Pumpkin]

Mine still has the 'kick' when pressing and letting off the accelerator, even in S mode. If it can't be fixed then that's fine, I'm just trying to make sure there are no underlying problems as my warranty expires soon.

[culzean]

I think that with lighter cars the anomalies of the transmission can be magnified.  A 3 ton vehicle will 'soak up' any jerkiness much better than a lightweight car like a Jazz. 

A torque converter is a fluid coupling that both interrupts the drive from engine to CVT (like a regular clutch) and  magnifies the engine torque by hydraulic means when car is pulling away,  then to reduce energy losses in torque converter a 'lock up' clutch engages and engine is now mechanically coupled to CVT box,  this engaging and disengaging of lock up clutch would hardly cause a jerk in a heavier car, but in a Jazz may be more noticeable.   Interesting article in link below, on pros and cons of different transmissions -  'automated manual' looks like Honda i-Shift and jerky changes are noted as one of the downsides of this type of transmission (as it used the normal clutch plate system like a manual shift), probably why it was short lived and Honda went to CVT for later models.

http://www.caradvice.com.au/278721/transmissions-explained-manual-v-automatic-v-dual-clutch-v-cvt-v-others/

As advised by Olduser1 I would certainly lodge a written complaint to Honda before warranty expires as a basis for future negotiations on this jerkiness.

[chrisv]

Hi,
Copies of the email correspondence are winging their way to your inbox,
Chris,
Let me know it has arrived

[Pumpkin]

Yep, received the email. Thank you very much!