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14 hours ago, cust1988 said:

a few weeks ago i traded  in my 2013 spark  for a 2016 spark cvt. it now has 500 miles on it.do these trannys need a break in period. it does not downshift into low gear unless you completely come to stop.it seems to shift strangely.

There's no real shifting on the CVT though some use computer generated virtual gears to mimic shifting . It doesn't work like a conventional automatic . It's just a belt riding on pulleys that change size to create a gear.ratio up and down as needed . The majority of times customers bring their cars in for service there's nothing wrong but just the way it functions . You may hear the motor rev high and think the trans is slipping but that just normal . Hopefully yours is fine and your just interpreting it as an issue .. If not then your under full warranty anyway. 

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On 9/3/2016 at 4:59 PM, sparkfanatic said:

There's no real shifting on the CVT though some use computer generated virtual gears to mimic shifting . It doesn't work like a conventional automatic . It's just a belt riding on pulleys that change size to create a gear.ratio up and down as needed . The majority of times customers bring their cars in for service there's nothing wrong but just the way it functions . You may hear the motor rev high and think the trans is slipping but that just normal . Hopefully yours is fine and your just interpreting it as an issue .. If not then your under full warranty anyway. 

Actually this is wrong. On the Jatco 7 there is a multispeed gearbox on the back of the CVT. That multispeed gearbox is what causes the shifting problems. They use that gear box to achieve a really low gear to get the car off the line and then shift into a high gear to get the fuel mileage. The gearbox is computer controlled and GM has had a very hard time getting the programming correct for it. This was a major issue for the 14 and 15's and obviously they still hadn't got it figured out.

Edited by Ray Dockrey
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3 hours ago, Ray Dockrey said:

Actually this is wrong. On the Jatco 7 there is a multispeed gearbox on the back of the CVT. That multispeed gearbox is what causes the shifting problems. They use that gear box to achieve a really low gear to get the car off the line and then shift into a high gear to get the fuel mileage. The gearbox is computer controlled and GM has had a very hard time getting the programming correct for it. This was a major issue for the 14 and 15's and obviously they still hadn't got it figured out.

That's only partially true . I agree it's a probably a tuning issue , at least in some cases and under certain conditions  The gearbox is nothing more than a couple planetary gears used to widen the ratios . The issue would be with the clutch or possibly the converter . The lockup not changing smoothly from high to low speed . Unfortunately as  I mention before   these issues apply to GM transmissions across the board and not limited to the CVT at all . Beyond that not everyone is affected by it or least bothered by it . The problem compounds when somebody isn't used to a CVT not to mention computer generated artificial shift points .

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  • 1 month later...
On 9/6/2016 at 8:12 PM, sparkfanatic said:

That's only partially true . I agree it's a probably a tuning issue , at least in some cases and under certain conditions  The gearbox is nothing more than a couple planetary gears used to widen the ratios . The issue would be with the clutch or possibly the converter . The lockup not changing smoothly from high to low speed . Unfortunately as  I mention before   these issues apply to GM transmissions across the board and not limited to the CVT at all . Beyond that not everyone is affected by it or least bothered by it . The problem compounds when somebody isn't used to a CVT not to mention computer generated artificial shift points .

totally agree with what sparkfanatic said

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  • 1 month later...

I don't own one yet I'm looking at buying one (pretty much sold on it)

but i thumbed through the owners manual and it does say there's a 500 mile break in period.

"

The vehicle does not need an elaborate break-in. But it will perform better in the long run if you follow these guidelines:

  • .  Do not drive at any one constant speed, fast or slow, for the first 805 km (500 mi). Do not make full-throttle starts. Avoid downshifting to brake or slow the vehicle.

  • .  Avoid making hard stops for the first 322 km (200 mi) or so. During this time the new brake linings are not yet broken in. Hard stops with new linings can mean premature wear and earlier replacement. Follow this "

doesnt really pertain much to the ops question but I figure it was worth sharing. Pretty standard break in recommendations 

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  • 3 months later...

My current car is 2017 Spark CVT LS. When A/C is not engaged, the CVT performs exceptionally smooth and solid. There is no hesitation, no jerks due to gear shifts, and prodigious power from the 1.4 liter 4 banger. However when the A/C is engaged, I noticed some engine revving and lag in response. My best guess is the computer   is trying to take into account the additional load of A/C, and something to get used to as characteristic of the computer software. Once the car gets rolling, the CVT behaves pretty normal.

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I think the short story on the Jatco-7 CVT in all Sparks from 2014-17 is that the engines just don't have the torque needed to properly run the CVT without some very tight programming tolerances that just don't seem to be in set properly out the factory door. Maybe the stock programming is for units without the A/C...thus the extra power/torque drain the tiny A/C compressor put to the engine upsets that tiny tolerance that is programmed into the one of the control modules...That's my take on that.

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  • 3 years later...

I have 2016 ls auto .and when taking off it falls on it face . Best way to describe it is having an older car with a carburetor that had a bad accelerator pump they would fall on their face when you took off how can we fix this issue every time I take it to Chevy they tell me that's just the way they are bull crap what can I do the car has 29,000 mi on it help it's been back to Chevy five or six times different dealers all say the same BS help me what to do what to say how to fix it

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  • 8 months later...
  • 1 month later...

Now 4.5 years old, my 2017 Spark LS tranny & engine are still running like a well oiled machine.

It starts at the flick of the ignition key, idles smooth as butter, and still has enough power to keep up with traffic at 70MPH.

The only problem I have noticed is if car is coasting at low speed (typically 5-15 mph) without foot on gas pedal, and if I press the gas pedal suddenly, the engine rev's up but the CVT does not catch up quickly and accelerate. That is the ONLY scenario when the CVT does not respond quickly. So I have learned to never stomp on the gas pedal at less than 20 mph, if in coasting mode.

 

After 4.5 years this 2017 Spark had no issues at all. No leaks, no breakdowns, no rattles. Only thing I have done is oil changes and changed air filter once.

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