General Motors has secured a significant legal victory that could affect hundreds of thousands of vehicle owners experiencing 8-speed transmission problems. The 6th U.S. Circuit Court of Appeals in Cincinnati voted 9-7 to decertify a class action lawsuit involving approximately 800,000 vehicles equipped with GM’s 8L45 or 8L90 eight-speed automatic transmissions.
The court determined that differences among affected vehicle owners were too substantial to justify a single class action lawsuit. Specifically, the judges cited the complexity of managing 26 statewide subclasses and 59 separate state-law claims within one unified case.
This decision reverses an earlier ruling from August 2024 by Circuit Judge Karen Nelson Moore, who had previously approved the class certification.
This legal development has serious implications for owners of 2015-2019 model year Chevrolet, GMC, and Cadillac vehicles equipped with these transmissions. The affected models include popular vehicles such as the Chevrolet Silverado, Colorado, Camaro, and Corvette; GMC Sierra, Canyon, and Yukon; and Cadillac CTS, CT6, and Escalade.
What This Means for Owners with the 8L45 or 8L90 Eight-Speed Transmissions
For owners of these GM vehicles, this ruling creates a more complicated path to seeking compensation for transmission problems. The class action would have allowed owners to join forces, sharing legal costs and potentially receiving settlements as a group. Now, the case returns to U.S. District Judge David Lawson in Detroit, who will need to consider whether smaller, more narrowly defined subclasses can still proceed with litigation.
GM successfully argued that the wide variability in how the transmission defects manifested across different states and vehicles made the case unsuitable for group litigation. This position prevailed despite the dissent from Judge Moore, who claimed the majority decision created nearly impossible barriers for plaintiffs filing class-action complaints against national manufacturers.
The Real-World Impact of GM’s 8-Speed Transmission Problems
What’s often lost in legal proceedings is the actual mechanical issue and its impact on everyday drivers. Owners have reported that vehicles with these transmissions shake and shudder at higher speeds and hesitate or lurch at lower speeds—problems that persist even after repair attempts.
Many owners have described alarming experiences, particularly during acceleration or deceleration. The transmission issues can make vehicles feel unsafe to drive, especially when merging into traffic or navigating busy highways.
On Reddit’s r/GMC and r/Chevrolet forums, owners have documented extensive problems with the 8L45 and 8L90 transmissions. One Silverado owner described the sensation as “feeling like you’re getting rear-ended every time you accelerate from a stop.” Another Sierra owner reported “violent shuddering between 45-65 mph that makes the whole truck vibrate.”
A Reddit user with username “SilveradoOwner2018” wrote: “My truck has been to the dealer 4 times for the same transmission issue. They flushed the fluid twice, replaced some valve body parts, and still can’t fix the shuddering. At this point, I feel stuck with a $45,000 truck that drives like it’s about to fall apart.”
Many owners report that dealerships have attempted various fixes, including transmission fluid flushes and valve body replacements, but problems frequently return. Some have even had entire transmissions replaced, only to experience the same issues with the new units.
GM 8-Speed Transmission Issues
The 8L45 and 8L90 transmissions were introduced as more fuel-efficient options with smoother shifting. However, technical analysis suggests the problems stem from internal hydraulic pressure issues and potential design flaws in the valve body and torque converter.
GM has issued multiple technical service bulletins (TSBs) related to these transmissions over the years, acknowledging the shuddering, hesitation, and harsh shifting problems. In 2019, GM released a new transmission fluid and flush procedure specifically designed to address the shuddering issues (GM Service Bulletin #18-NA-355).
The transmission problems appear to affect vehicles across multiple model years and brands within GM’s lineup, suggesting a fundamental design or manufacturing issue rather than isolated incidents. This widespread nature of the problem formed the basis for the class action, which sought to hold GM accountable for knowingly selling vehicles with defective transmissions.
What GM vehicles are affected?
The 8-speed transmission was used in a variety of vehicles from 2015 to March 1, 2019:
- 2015-2019 Chevrolet Silverado
- 2017-2019 Chevrolet Colorado
- 2015-2019 Chevrolet Corvette
- 2016-2019 Chevrolet Camaro
- 2015-2019 Cadillac Escalade and Escalade ESV
- 2016-2019 Cadillac ATS, ATS-V, CTS, CT6, and CTS-V
- 2015-2019 GMC Sierra, Yukon, Yukon XL, and Yukon Denali XL
- 2017-2019 GMC Canyon
According to the lawsuit, there have been 13 technical service bulletins, TSBs, to fix this issue with no resolution.
What Options Remain for Affected Owners?
While the class action has been decertified, affected owners still have several potential paths forward:
- Smaller class actions: The court’s decision allows for the possibility of smaller, more focused class actions that might be certified.
- Individual lawsuits: Owners with significant damages could pursue individual legal action, though this is typically more expensive.
- Lemon law claims: Depending on the state, owners who’ve had multiple unsuccessful repair attempts may qualify for relief under state lemon laws.
- Warranty claims: Those still under warranty should continue documenting all transmission issues and seeking repairs through authorized dealers.
- Stay informed: Owners should monitor developments in this case, as the judge may still certify smaller classes of plaintiffs.
The court’s decision doesn’t deny that there are problems with these transmissions—it simply ruled that the legal mechanism of a single, nationwide class action isn’t appropriate given the variations in state laws and individual circumstances.
For the hundreds of thousands of GM vehicle owners experiencing these transmission problems, the legal path forward just became more complex, but not necessarily closed. The next phase of this legal battle will determine whether any consolidated actions can proceed and what form of redress might eventually be available to those affected by these persistent transmission issues.
Managing Editor
Christopher is an automotive technical writer. When he’s not at the local autocross event, he can often be found working on one of his cars. Specializes in automotive class action law, industry trends, and automotive maintenance. Email me direct, or learn more about us
De
October 10, 2025 at 4:04 pmMy 2020 Canyon had the same problem, Manufactured 08/19. Includes more vehicles than reported.
Preston Hegar
September 24, 2025 at 3:10 pmFather-n-law left me his canyon when he passed away. Was out of warranty by that time but only 26’000 miles on it. He wanted me to pass it on to his great grandkids. Won’t happen!!!!!!!! 3000 miles later, fluid flush and filter change then a new torque convertor and I’m scared to drive it on the highway! I would bet that the Leadership of GM wouldn’t let their family drive it. No one will buy it because of the shudder. It is a great looking Garage ornament.
Daniel Glover
September 19, 2025 at 7:04 pmbought my gmc sierra used i didn’t notice the problem wright off, after about 2 months it started, talked to my mechanic he told me to put an additive in it if the problem stopped my transmission was going bad. cost me 5.000 to get it fixed the mechanic that rebuilt told me not to pull anything with this truck, said that it would negate the warranty. one of the reasons i bought the truck was to haul by boat back and forth to the lake. in less than 2 years i am in the same shape. pull out at times and it lurches also reverse does the same. no fix i will tell everybody i know do not buy any gm made vehical!
Brian H
August 11, 2025 at 4:41 pmDone with GM !!! Im on 3rd transmission
RJ
July 18, 2025 at 1:52 pmI am a lifelong Chevy owner. I was hoping for Chevy to have a resolution to this problem that they created. But it looks like they are just happy to Lawyer Up. I’ll just join the line down at the Toyota Dealership and enjoy my new Tundra. i tell all my friends, “Just don’t get a Chevy.”
William Montgomery
July 10, 2025 at 9:18 amMy transmission problem stems from the dealer absolutely offering no solutions to my shifting transmission problems. Other then the computer has to get use to my driving habits. (REALLY). After requesting help several times and being told nothing could be found wrong. I just continued to drive the truck until with the dangerous shifting problems until it failed while driving out of state. The GM dealer in that state said that the torque converter was coming apart and pieces of metal from the converter entered the transmission causing it to fail. That dealership said this was a common problem with these transmissions. Cost out of pocket to rebuild $4,500. I almost felt that the Dealership I purchased the truck from was not honest from the start.
James Stafford
July 9, 2025 at 8:51 pmI have bought.GM for yrs since 1985 however I will be buying Toyota from now.on goodbye GM
Memedic95
July 1, 2025 at 6:36 pmI’m not staying with GM if they don’t make this right. I bought this truck to be my forever truck being over 60. I can’t afford this crap.
Clyde
July 1, 2025 at 8:10 amCongratulations on the win Chevy! Enjoy it, but I’m buying a Toyota now. Good luck!
Chris Rossen
July 1, 2025 at 8:32 amThis seems to be the reaction from customers. Long time GM fans continue to stay with the brand however.
David Moore
July 12, 2025 at 10:03 amGood luck with your Toy Clyde. I dumped my 2018 Chevrolet Colorado Centennial Edition (one of 338 long be crew cabs) and bought a 2021 Tacoma Limited, new. I HATE THE TRUCK!!!!
Let me repeat that, I. HATE. THE. TACOMA. The transmission shudders, although not as bad as the Colorado, but it shudders. Toyota says it’s normal, that it is operating as designed, that there is NO problem with the truck.
The Taco also gets dismal fuel mileage. Where my Colorado got 22-24 mpg the Taco barely makes 16-18. The transmission downshifts at the mere hint of a hill if you’re trying to even maintain 55 mph. I’ve been told that the Tundra is even worse, with barely 14 most of the time on a good day.