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New CVT issue ( shuttering and clunking)


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I have noticed a couple times recently if I don't come to a complete stop, maybe going around 5mph then give it has the transmission will shutter and shake the car befor grabbing and accelerating. Today as I was approaching an intersection and was slowing, the light turned green, as I got on the accelerator the transmission made a big clunk noise and the car lurched.

Has anyone else had this issue? I am calling the dealer in a little bit to get an appointment.

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Mine does it too. I wondered if somebody else was seeing the same thing. Started immediately after the software update. My guess is it shifts late, binds the CVT up just a bit and the steel belt slips. Mine does it the exact same way. Only does it when you you just about to stop then take off.

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I have noticed a couple times recently if I don't come to a complete stop, maybe going around 5mph then give it has the transmission will shutter and shake the car befor grabbing and accelerating. Today as I was approaching an intersection and was slowing, the light turned green, as I got on the accelerator the transmission made a big clunk noise and the car lurched.

Has anyone else had this issue? I am calling the dealer in a little bit to get an appointment.

Hey Angrybird12,

If you need any assistance with this further, we are always happy to look into this further on our end as well. Looking forward to your updates from your appointment!

Patsy G

Chevrolet Customer Care

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I haven't had any trouble since the update. From a complete stop, a slow smooth acceleration doesnt really happen, little rev then a surge forward like the gear clicked in.. nothing crazy and probably not even noticeable to a passenger, nothing really to complain about either. does the little bunny hop thing when going down a drive way slowly every once and a while but much much less than before the update. I have been driving much more aggressive lately not trying conserve gas, still getting 32mpg in the city versus the 36 i was getting but it seems to have adapted to this driving style and has much more get up and go. when i was driving to conserve gas it seemed to adapt to that and not have the acceleration i wanted when needed like it was set in an eco mode and now its in a sport mode.. i dunno.. keep us posted on what happens

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Today it did it a little bit one time, AC was not on and it was around 75 Degrees.

I am going to wait a little longer and notice the exact circumstances when it occurs and if I can duplicate the conditions so the service people will know how to make it act up. Right now there seems to be no pattern.

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i edited this to add that it did it twice to me this morning with the AC off. First time that I have noticed it but did want to report that is happening with the AC off. I haven't worried about too much since the trans is covered under warranty and the update has. made such a tremendous difference. I don't know if they could but I wouldn't want to have to go back to the way it was.

Edited by Ray Dockrey
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  • 1 month later...

I just bought my spark have less than 500 miles and have notices this shutter under the above mention conditions. planning on going back to the dealer for a couple other things and wasn't sure if this shuddering was from me taking it easy and not use to the CVT but defiantly going to ask about this.

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My 2015 1LT has been doing the bunny hop almost since new. Only on slow take offs, which is how I drive. Had it to the dealer at about 3000 miles (now has 4800 miles on the odo) I kept telling myself it wasn't that bad and was living with it. It did seem to be getting worse so I took it in. They kept it over night and found everything NORMAL. Well I am still trying to live with it BUT sometimes it is really bad, bucking so bad that I just can't keep ignoring it. Thankfully, it doesn't hop real hard most of the time. At first it seemed only on first take off after starting it up. Now it will do it any time. Sad part is....I love everything else about this car and would be bragging all over the place. I feel guilty every time someone asks me how I like it. I just tell them I love it. (which I do) but I don't mention the hop problem. How sad am I? I am going to try taking it back to the dealer soon. I promise.

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My 2015 1LT has been doing the bunny hop almost since new. Only on slow take offs, which is how I drive. Had it to the dealer at about 3000 miles (now has 4800 miles on the odo) I kept telling myself it wasn't that bad and was living with it. It did seem to be getting worse so I took it in. They kept it over night and found everything NORMAL. Well I am still trying to live with it BUT sometimes it is really bad, bucking so bad that I just can't keep ignoring it. Thankfully, it doesn't hop real hard most of the time. At first it seemed only on first take off after starting it up. Now it will do it any time. Sad part is....I love everything else about this car and would be bragging all over the place. I feel guilty every time someone asks me how I like it. I just tell them I love it. (which I do) but I don't mention the hop problem. How sad am I? I am going to try taking it back to the dealer soon. I promise.

Have the tech ride with you so they can experience it and you can point out what's happening.

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  • 6 months later...

Here it is March 2016 and I am still putting up with the bucking problem. I keep telling myself that I need to take it to the dealer again, but I hate to go there. The problem has not really gotten any worse, even thru the (not very cold) winter. Low and behold, I just got a letter from GM to bring my car in for a (wait for it) "transmission software update."

So as soon as I can I will check this out.

Still lovin the car other wise. Got about 10900 miles on it so far....Anyway, wish me luck. :o)

Edited by geogary
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This particular CVT was designed specifically for small engines with low power output and has incorporated a secondary gearbox...It's a relative new design by Jatco, one of the world largest CVT producers. The idea is to have the car run at lower and more constant RPM's. This can result in some sluggish performance and at lower speeds where the car rpm's are low enough to cause the 'bucking' due to the very low torque at low rpms...electronically controlled means it can actually be re-programmed to change the power band up or down on the gear ratio controller..this is fortunate because in my opinion this CVT has a poor design and prone to belt failure/damage and runs very hot. Fortunately GM has found a fix for the range controller programming and replacing the 'out of spec' belts via recall. Another good thing is that the CVT is part of the powertrain and subject to the 5/100,000 warranty so that alone should go a long way to ensure users they will not be out-of-pocket for any issues that may pop up in the future.

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  • 2 months later...

Took it to the dealer for "Transmission Software Update".....Did not notice an improvement in the bucking problem. In fact I did not notice any difference at all. However at first I imagined an improvement, but I figure it was my wishful thinking. Sometimes now it actually seems worse. I just said to the wife the other day that I should take it back to the dealer, but I am afraid they might mess up my gas milage or something worse. I can stop the bucking if I let off the gas OR step on it to go faster. What a shame....I might actually be getting an engine miss fire now. I put a tank of high test in a couple of weeks ago and it seemed to make the engine miss at times. This was a different jerking than the transmission. Probably the only reason I am putting up with this is, I am from a time when there were manual chokes on cars and they all mostly ran like crap till they were pretty well warmed up. By the way, since I went back to regular gas it does seem to be doing better on the missing part, but not the tranny hop thing.

Still averaging over 41mpg after averaging all the milage and gas purchases since day one. Now have 13,312 miles with one trip up north (about 3000 miles) and the rest all local driving, mostly city with maybe a third of that on interstate. Last fill up was 43.33 mpg. :o) I have been using almost exclusively Mobil regular and have used synthetic oil since first oil change at about 900 miles.

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Probably the only reason I am putting up with this is, I am from a time when there were manual chokes on cars and they all mostly ran like crap till they were pretty well warmed up. By the way, since I went back to regular gas it does seem to be doing better on the missing part, but not the tranny hop thing.

Roger that! It's the CVT that is the issue..complain and have it looked after as best they can do since the CVT's in the '14-'16 are just a badly engineered design...Regular gas is best..more combustible..I too am an old timer and, yes, I do remember driving a pull choke..same even on some smaller piston aircraft...Good luck, but fight if you are not happy as you are not alone with this issue..

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  • 2 months later...

During a free oil change and tire rotation (dealer coupon), and while waiting, I decided to test drive a new 2016 with CVT and another 2016 with manual tranny.

Night and day between the CVT and the manual! CVT was a slug that would barely get off the lot as it seemed to start in second gear, then drop to first then back to another gear, revving, then sudden drop in revs then back up...same on the freeway on ramp.. no acceleration then sudden revs and off it went...fairly smooth at 60mph and over. Manual same route..much more power and smooth shifting. Can't see why GM is even allowed to sell the CVT version..completely unsafe and a scary slug to drive...brand new unit. Apparantly...no changes for 2017...so I can't imagine this CVT Spark will last long once sales figures for 2016 are in...That's my take on that...'Nuff said...

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My does the same thing. Took it for test drive with two different dealership and both mechanics experienced it and said its normal and it supposed to do that. Can't be good for any of the engine. The mechanic told me it was messed up when it does that, went to his computer was gone for about 30 minutes and came back said its normal 

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15 hours ago, Flygrl said:

My does the same thing. Took it for test drive with two different dealership and both mechanics experienced it and said its normal and it supposed to do that. Can't be good for any of the engine. The mechanic told me it was messed up when it does that, went to his computer was gone for about 30 minutes and came back said its normal 

I agree that this kinda erratic shifting can be very hard on any engine but more so on a VVT engine...certainly this can't be 'normal' and would also put a lot of stress on the CVT components...I think that GM has not yet found a solution in their dealings with the Jatco7 CVT supplier, thus the techs have no info on a fix other than permission to replace in certain situations...that is what I would push for.

*I can see the CVT not working properly on the small 1.25L engines, but the new 1.4L have enough and wide band torque that I just can't see it not working to spec unless there is a design flaw with the double gearbox CVT's...

Edited by Retired old Gearhead
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Both dealership techs experienced it when they drove with me and both said abnormal until they go to their computer then they come back and say normal. Also this last time my check engine light came on when it bucked like that and codes popped up on onstar but the dealership said it was in the history so now my car is just throwing old codes and did a reset of the codes, no fix??? Funny how onstar state otherwise and sent me a letter with all the codes that popped up during last bucking. This time the dealership has had my car for two weeks and also my AC is also leaking on a car not a year old yet, told me to drive it back to home which i have literally been stranding for 2 weeks and no the dealership didn't provide a loaner and I'm 8 hours from home. 

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11 hours ago, Retired old Gearhead said:

I agree that this kinda erratic shifting can be very hard on any engine but more so on a VVT engine...certainly this can't be 'normal' and would also put a lot of stress on the CVT components...I think that GM has not yet found a solution in their dealings with the Jatco7 CVT supplier, thus the techs have no info on a fix other than permission to replace in certain situations...that is what I would push for.

*I can see the CVT not working properly on the small 1.25L engines, but the new 1.4L have enough and wide band torque that I just can't see it not working to spec unless there is a design flaw with the double gearbox CVT's...

It took Nissan threatening To pull out from Jatco before Jatco complied to fix the Nissan CVT 

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