Angrybird12

CVT shifting issues and new TSB PI1309

91 posts in this topic

9 hours ago, VegasSpark said:

I stopped by my dealer today, to ask about the bouncing. (I have video proof, and it did it again going in to the dealer)

The suggestion i was given was to try 91 gas from a top teir station. (Chevron, arco, shell, ect) and to avoid cheaper gas (smiths, sams club, costco).

He said the bouncing could be from air in the line from gas boiling. (Its been consitantly 110+ recently) if that doesnt help, to bring it back in. He was also surprised it was only bouncing and not stalling, which is why he recommended the gas change. (During these hot months)

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The mechanic seems knowledgeable by the fact he is familiar with 'vapor lock' caused by fuel boiling or air in the line... sometimes caused the gas boiling. Switching to a less volatile octane # (91) or gas without ethanol would help... if vapor lock was the issue. I have encountered this (vapor lock) in older piston aircraft flying in hot weather above 9,500 ft and the result is a scary engine stall and hard to start again without lowering altitude. Hard to imagine this happening in a modern car since the fuel pump is quite cool submerged in the fuel tank, but not impossible at high ambient temp or combined with the vehicle being driven at higher altitudes and there are some areas around Vegas that are ++2,500ft ASL...so he may have a very valid point. Although vapor lock is now fairly rare due to improved location and design of fuel delivery systems..it can happen.

 

      IMO, the bouncing is similar as described by others with the cause being the CVT not finding the right gear and then dropping the gear for another quite suddenly. This would be a CVT tranny hardware or software issue and the fact you have to turn off the A/C to start from a stop with passengers leads me to think the tranny is not dropping to first gear at stop, which along with the overdrive gear, is controlled by the aux/attached auto gearbox....OK..I know..TMI, but that's my take on this stuff.....

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I highly doubt its vapor lock. Most modern cars don't suffer from that. But I do believe its the CVT as mine does that sometimes. It used to be really bad when driving at slow speeds like through a parking lot but it has got much better with the new programming. Its just one of the quirks with the transmission.

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4 hours ago, Retired old Gearhead said:

The mechanic seems knowledgeable by the fact he is familiar with 'vapor lock' caused by fuel boiling or air in the line... sometimes caused the gas boiling. Switching to a less volatile octane # (91) or gas without ethanol would help... if vapor lock was the issue. I have encountered this (vapor lock) in older piston aircraft flying in hot weather above 9,500 ft and the result is a scary engine stall and hard to start again without lowering altitude. Hard to imagine this happening in a modern car since the fuel pump is quite cool submerged in the fuel tank, but not impossible at high ambient temp or combined with the vehicle being driven at higher altitudes and there are some areas around Vegas that are ++2,500ft ASL...so he may have a very valid point. Although vapor lock is now fairly rare due to improved location and design of fuel delivery systems..it can happen.

I also have a feeling that it isnt vapor locking. But one tank of 91 gas in this car wont be too much more of a cost to try it out. 

On the otherhand, i would be surprised if it was heat related. Both days its acted up were 115+ days with the ambient air readings inside the car ranging from 119-128, with moderate traffic and an hour of driving. Some pretty nice conditions to build up some heat. 

 

Either way, we will know in a week if it is vapor locking. (Thats when ill need a refuel on gas, AND it looks like our last 110+ days are coming to an end for this year.)

 

I really like this mechanic. He's been insanely helpful with everything going on, and actually listens. He suggested to try this first, and come back if it didn't help. (He also mentioned he's seen it in a few sparks and cruzs in the past two weeks here)

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15 minutes ago, VegasSpark said:

ambient air readings inside the car ranging from 119-128

Why not just turn on the A/C..that's the button with the snowflake symbol....B)

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My 2014 lt2 has 20000 miles I've complained several times to the dealer they keep saying no codes for the transmission  it's been updated mine has been starting out in the wrong gear it sometimes corrects itself after you start moving then it revs and acts like its slipping . It's also started this shuddering like its trying to shift and can't iam sure it will get worse and fail I guess after it fails they will have to replace it . It's really too bad Chevrolet doesn't have a fix for all these transmission issues .

 

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Update: I got a new transmission, and still have the same problem. Chevy now says that the slow acceleration from stop in the heat is just the way the car drives. Unacceptable that Chevy would manufacturer such a car, as the end user often wouldn't figure this out until after owning the car awhile. Too many problems with my car, so I traded it in for a Volkswagen. It's a shame, because I come from a Chevy family and have always loved Chevys.

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6 hours ago, GuyFromMars said:

Update: I got a new transmission, and still have the same problem. Chevy now says that the slow acceleration from stop in the heat is just the way the car drives. Unacceptable that Chevy would manufacturer such a car, as the end user often wouldn't figure this out until after owning the car awhile. Too many problems with my car, so I traded it in for a Volkswagen. It's a shame, because I come from a Chevy family and have always loved Chevys.

Probably a wise move since the replacement CVT's are exactly the same Jatco-7 that are in the Sparks now...so a new tranny may or may not last long without issues. Basically some dealers are saying "Turn off A/C to get car rolling" and in your case..."slow acceleration from stop in the heat is just the way the car drives".

Translation: this tranny does not work as designed in the Spark.

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58 days later I got my spark back!

 

It seems to be doing a TON better.  No more jerking when I come to a stop, no more of the transmission not knowing when to shift, accelerates smoother.

 

I noticed I don't have to take foot off of accelerator to make it shift into 4th or 5th I think it is so I'm happy as a clam.  It appeared I just had a bad tranny!

 

NOT HAPPY however- I got a little scratch on the bumper and they tried to gouge me for 500.  I dropped a flurry of F BOMBS demanded my keys and the sales manager came up and tried to haggle with me.  I walked out of there paying nothing.  I hope I don't get a bill.

 

And why Should I?  They billed chevy 2,000 for my rentals, another 2300 for my transmission.  Go after them for the scratch IDGAF.  58 days to service a vehicle is unacceptable!

 

 

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Wow..2 months! Did they fix or replace the CVT tranny? $500???..For warranty work?...You did the right thing..walk away and if you do get a bill..which I highly doubt..send it in to GM HQ..customer service with a polite letter..

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According to the link they sent me, there is no invoice, there is no bill.  I walked away.  It was for the scratch not the warranty.  0$ out of pocket.

 

They replaced it.  They said they had to run diagnostics first per chevy instructions but they said it needed a new one altogether. 

 

Apparently one was en route a month ago but it got lost?  It finally came hahaha!

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On 8/26/2016 at 1:57 PM, TheThickness said:

And why Should I?  They billed chevy 2,000 for my rentals, another 2300 for my transmission.  Go after them for the scratch IDGAF.  58 days to service a vehicle is unacceptable!

If the scratch is on the bumper area or infact anywhere on the front plastic unit, it can easily be touched up without that area prone to rust as it is made from a non metal material...I think the dealer wanted to bill you for replacement of that unit as they rarely get involved in body work. As far as the dealer billing GM, the tranny was not billed to GM, it is considered a GM stock part and thus shipped with GM absorbing the cost...still the whole tranny swap is a costly item for GM considering the labor bill and the cost of hardware replaced....specially when you consider how many of these extra units they have to purchase from Jatco and then pay the dealers for the many they had to replace.

     Hope this one works properly for you!

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On Thursday, July 28, 2016 at 7:31 AM, Retired old Gearhead said:

Why not just turn on the A/C..that's the button with the snowflake symbol....B)

 

Since i started this in this thread.... if I get any actual news ill break off to another thread.

 

With the 91 in the car, it randomly accelerated. So I dropped back down to the standard gas. To which it responded by having no response the other day when i hit the gas. Its at the shop right now, and this poor mechanic must be tired of seeing me by this point.

 

Edit: surprise surprise. They couldn't find anything. :/

Though therr was a camero in for the shutting off on the freeway thing. And two other sparks in the drop off bay when i dropped off.

Edited by VegasSpark

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I know this is an older post but I have a 2015 spark already had the tranny replaced once because it went completely out now I'm having problems again and like before they are telling me it's normal. Like before when telling me it's normal for it to "hesitate" when taking off in shifting they waiting until codes popped up and they barely made it back to the dealership with my car. I'm at my wits end. I love my car not my tranny. Any advice?

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36 minutes ago, Spark2015 said:

I know this is an older post but I have a 2015 spark already had the tranny replaced once because it went completely out now I'm having problems again and like before they are telling me it's normal. Like before when telling me it's normal for it to "hesitate" when taking off in shifting they waiting until codes popped up and they barely made it back to the dealership with my car. I'm at my wits end. I love my car not my tranny. Any advice?

 

Click on the link and briefly explain your issue. Ask about a buyback and they'll look into all the work they've done and if you're still having issues they'll explore your options.

 

https://www.gm.com/site-help/contact-us/email-us.html

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On ‎5‎/‎6‎/‎2015 at 2:34 PM, robdotexe said:

I have been experiencing this exact problem. When coming up to a complete stop, it hesitates to drop to the lowest gear. When taking off, it feels horrible. I have taken it in a few times and was told that it was "normal operation". :(

they had to replace mine last month for the same problem. it completely failed to work. under warranty for 100009 miles. I would make them replace it asap.

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Posted (edited)

After 3 months of experiencing that quirk with my 2017 CVT, I have learned how to work around it, and have no more issues with CVT behavior.

 

The quirky behavior was occurring only when car was moving between 10-20 mph (such as in parking lots or coasting towards a red light which turned green at intersection) and I stomped on the gas pedal to accelerate quickly. Now in that speed range, I press the gas pedal slowly, and the CVT catches up appropriately. At speeds above 20 mph, stomping on the gas pedal works fine.

Edited by Bobby MSME

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