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'14 CTS-V LongRoof; '16 ATS-V Sedan,' 04 Trailblazer 4x4; '10 CTS LongRoof gone but never forgotten
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Discussion Starter #1
From GM Authority:

[h=1]The GM 8-Speed Transmission Needs To Go Away ASAP: Opinion[/h]


It’s no secret that the GM 8-speed transmission is not great. Also known as the 8L90 and 8L45, the 8-speed pairs to rear-wheel-drive architectures in GM’s bread-and-butter products, including pickup trucks, SUVs, sports cars and luxury cars, and to say that it has a few issues would be a major understatement. Owners have complained far and wide about the 8-speed’s strange tendencies, such as waiting too long to upshift, downshifting at odd times and lurching when coasting or coming to a stop light. Long story short, GM needs to do away with the 8-speed and replace it with the much-improved 10-speed automatic… and quick.
In fact, GM was recently slapped with a class action lawsuit over the 8-speed gearbox. The plaintiffs assert the GM 8-speed transmission is defective, creating violent shakes, jerks, and a “hard shift” when selecting a gear. For its part, GM has filed 13 technical service bulletins concerning the unit, none of which remedied the issue. Following the lawsuit, more owners have spoken out over the issue, and we’ve even heard from our own readers about it on our forums.
The issue seems to be most common when accelerating or decelerating as the transmission tries to find another gear, with the problem believed to stem from the torque converter as well as the gearbox’s shifting logic.
Following a litany of complaints, GM tried to “improve” the 8-speed in the 2019 Silverado and 2019 Sierra. In a press release, the automaker said it made “enhancements designed to improve shift quality, while also adding a new centrifugal pendulum absorber torque converter” to improve smoothness. The new revised transmission was assigned RPO code MQE, replacing the M5U 8-speed unit on the half-ton Silverado and Sierra, but not (yet) on other GM products like full-size SUVs or mid-size pickups.
Taking all that into consideration, The General seems to have grossly mishandled the entire situation with the 8-speed transmission. What it should have done is replaced the GM 8-speed transmission outright with its new 10-speed automatic (jointly developed with Ford) in every vehicle application. Of course, that would have required some doing, as the GM product lines that would qualify for the change-over today include:

Previously, the GM 8-speed transmission was also used in sunset models like the Cadillac ATS, third-gen Cadillac CTS (except for the CTS V-Sport, which used an Aisin eight-speed), and the 2016-2018 Cadillac CT6 (the vehicle switched to the 10-speed transmission for the 2019 model year). In addition, the GM 8-speed transmission was also used in the 2016-2018 Camaro LT and SS, along with the now-discontinued C7 Corvette (apparently the 10-speed was too wide to fit into the C7).
[h=3]The GM Authority Take[/h]To play armchair quarterback for a quick minute, The General should have bitten the bullet and replaced the GM 8-speed automatic transmission in any applicable vehicles with the new 10-speed unit as soon as the new 10-speed was launched, no matter if the model was due for an update, refresh, or overhaul, or not. Instead, The General dug its heels in and continued to offer vehicles with the lackluster 8-speed, going so far as to launch all-new products – most notably the 2019 Silverado and 2019 Sierra – with the 8-speed that was “improved,” but that didn’t deliver any noticeable improvements.
Sure, switching to the 10-speed mid-stride would have created additional expenses and required additional engineering work. So yes, it would have cost GM money. But wouldn’t those funds have been well-spent when compared to the gobs of money GM will probably end up spending in legal fees to defend itself (and potentially pay out on the class action), while also causing reputation-based damage as a result of customer dissatisfaction in its bread-and-butter products, thereby potentially losing customers for life?
Why, yes it would have.



Read more: http://gmauthority.com/blog/2019/06...ion-just-needs-to-go-away-asap/#ixzz5rE2lWBYA
 

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2016 ATS-V
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649 Posts
Terrible transmission! Harsh, finicky, and sluggish - adjectives you'd want to avoid when describing a transmission.

To date, the best automatic transmission I've owned was the 5-speed found in the 2006 Acura TSX. The transmission was quicker to shift and had excellent engine braking, excellent control.
 

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I haven't had any problems with my ATS-V's transmission. I agree that it is not the best. BMW makes a great dual clutch transmission, but very costly to fix.
 

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'14 CTS-V LongRoof; '16 ATS-V Sedan,' 04 Trailblazer 4x4; '10 CTS LongRoof gone but never forgotten
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15,425 Posts
Discussion Starter #4
I've had mine in twice for the herky-jerky. My dealer had never heard of the latest TSB. I had to tell them about it which is why I went back a second time.
 

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2016 ATS-V, 1969 Cougar XR7 Convertible, 1970 GTO, 1970 Torino GT, 2006 XLR
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174 Posts
I have a late year 2016 ATS-V and except for the very first 1/2 shift of the day, I have absolutely NO issues with this transmission for the rest of the day. I have learned that if I allow the oil temperature to come up a bitin the morning by idling the car for about 5/6 minutes, the harsh 1/2 shift is virtually eliminated.
 

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ATS-V
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53 Posts
Had my fluid flushed under warranty, a replaced torque converter under warranty and another recent flush on my dollar. This morning, had a violent bang shift, 1 to 2 gear, on a fully warmed up tranny. I'm afraid we are going to have to live with this problem to the very end. Shame....the tranny was brilliant at COTA!!
 

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2016 ATS-V Coupe (Catti-V)
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Had my fluid flushed under warranty, a replaced torque converter under warranty and another recent flush on my dollar. This morning, had a violent bang shift, 1 to 2 gear, on a fully warmed up tranny. I'm afraid we are going to have to live with this problem to the very end. Shame....the tranny was brilliant at COTA!!
the bottom line is that harsh 1-2 shift is just a characteristic of this transmission that is never going to go away. GM is not going to spend the money thats necessary to fix this transmission. I'm okay with that because under normal driving conditions, especially under hard acceleration, this transmission does excellent.
 

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Ats-V
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Mine does not have any issues, and has been my second favorite transmission of all the 22 vehicles I have owned so far. The only one I have liked better has been the ZF 8 speed.
 

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ATS-V
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Had the flush done, appears to have sorted out the shudder, which was in it's beginning stages on my car. I wasn't getting the rumble strips effect, but rather a stuttering at low throttle in high gear when going uphill. I also had the coupling/uncoupling at highway cruise. Seems to all be gone now. As others have stated, the 1-2 is still sometimes harsh, but that is always after a first startup.. doesn't seem to matter whether the car is warm or cold. The "fix" for me has always been to start out in M1 when I am going through a parking lot, etc.

I'm eager to see if a recall will happen. I just think there will be lots of resistance to it from the bean counters at GM, because of the number of vehicles that have the 8L90. It will be a very expensive recall for them, even if they limit the work to a flush and valve body replacement. Replacing the TC on tens, maybe hundreds of thousands of vehicles will be very costly, and I could 110% see GM trying to weasel out of that.
 

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2016 ATS-V Sedan Crystal White Tricoat
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Had the flush done, appears to have sorted out the shudder, which was in it's beginning stages on my car. I wasn't getting the rumble strips effect, but rather a stuttering at low throttle in high gear when going uphill. I also had the coupling/uncoupling at highway cruise. Seems to all be gone now. As others have stated, the 1-2 is still sometimes harsh, but that is always after a first startup.. doesn't seem to matter whether the car is warm or cold. The "fix" for me has always been to start out in M1 when I am going through a parking lot, etc.
So I just had mine done too, for the exact same issue. The shudder and coupling/uncoupling at highway cruise is gone. However, the issue persists where gears 2-3, 3-4, 5-6 are a bit harsh and sometimes it feels like the gear is slipping a little bit. Does your car exhibit those symptoms? I have the dreaded 1-2 when I first drive off in the morning but after that the 1-2 is fine.
 

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So I just had mine done too, for the exact same issue. The shudder and coupling/uncoupling at highway cruise is gone. However, the issue persists where gears 2-3, 3-4, 5-6 are a bit harsh and sometimes it feels like the gear is slipping a little bit. Does your car exhibit those symptoms? I have the dreaded 1-2 when I first drive off in the morning but after that the 1-2 is fine.
Hi,

I do get the slippage occasionally, but it's pretty infrequent and usually occurs when I am turning and going up an incline at low speed. I don't think it's happened since the flush, but I will watch for it now that you have mentioned it.
 

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I believe the latest shudder TSB has been posted her. Need to search for it. It is in 2 parts and many pages long as it covers all the cars using the A8.

I have two 8L90s. The one in my 16 Corvette Z06 is not terrible but definitely is not as good as the one in the 18 ATS-V. So they have made some improvements.
 

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'16 ATS-V MT6 Sedan, Alfas: '67 Duetto, '84 GTV6 3.5L 24v/Vette C5 project
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2016 ATS-V Coupe
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I went in last week and they did 3 software update. Today it ran worse. I will bring it back to have the fluid changed. If I can get running a Babette’s I will sell it and get a BMW or Audi. I am just so sad. I love this car.
 

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2016 ATS-V Coupe
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I posted this in the general discussion area, but since this is a Tranny thread - GM not alone as a domestic car manufacturer with transmission headaches. Seems Ford might be more complicit in their problems....

Fords always stunk. I thought GM were supposed to gone solid
So I just had mine done too, for the exact same issue. The shudder and coupling/uncoupling at highway cruise is gone. However, the issue persists where gears 2-3, 3-4, 5-6 are a bit harsh and sometimes it feels like the gear is slipping a little bit. Does your car exhibit those symptoms? I have the dreaded 1-2 when I first drive off in the morning but after that the 1-2 is fine.
mi e runs poorly when hot
 
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