GM 8 Speed Transmission Problems

GM 8 Speed Transmission Problems Leads to Another Class Action Lawsuit

Have you had problems with your GM 8L45 or 8L90 transmission? If so, you’re not alone. In fact, so many people have had issues with this transmission that there is now another class action lawsuit against GM. If you’re a car owner with this transmission, read on to learn more about the lawsuit and what it could mean for you.

GM 8 Speed Transmission Problems and Complaints Explained

Owner complaints allege that vehicles equipped with GM’s 8L45E and 8L90 automatic transmissions are prone to a handful of problems. Problems such as: slipping gears, shifting into gears aggressively, shuddering or jerking, delayed acceleration, and having trouble slowing down. Additionally, the lawsuit claims dealerships began getting complaints from customers as early as September 2014, and GM should have known that these defects would adversely affect drivability.

The lawsuit also alleges these defects present a safety hazard as they severely affect the driver’s ability to control the vehicle speed, acceleration and deceleration.

GM’s 8L90 and 8L45 Transmissions Suffer from Similar Defects as the 6L50 Transmission

Vehicles with the 6L transmission lodged similar complaints with NHTSA as far as 2008. Owner complaints with the 6L transmission are very similar to those seen in the GM 8 speed transmission. Because the 8 speed transmission is based on the 6L, it’s no surprise that there are similar defects.

GM Vehicles Affected

The following vehicles are affected by the alleged GM 8 speed transmission defect:

Status of the GM 8 Speed Transmission Class Action Lawsuit

Class Action Currently Active

Won v. General Motors LLC (E.D. MI. Case No. 2:19-cv-11044-DML-DRG) is a class action lawsuit filed on April 10, 2019, which was consolidated with lawsuits filed by several other consumers on behalf of people who purchased or leased certain cars equipped with a 8L45 or 8L90 GM transmission.

Previously Filled GM 8 Speed Transmission Lawsuits

  1. Shelton, et al. v. General Motors, Case No. 19-11802
  2. Ray v. General Motors, Case No. 19-11808
  3. Duffy, et al. v. General Motors, Case No. 19-11875
  4. Gutierrez, et al. v. General Motors, Case, No. 19-12371

What Some Owners are Saying About Their GM 8 Speed Transmission Problems

I just purchased a 2017 Denali with the 8 speed. The truck had 42K miles on it when I got it when I test drove it I felt the transmission act just a little bit different shifting but it was such a damn good looking truck I pulled the trigger. Now I’ve only put 500 miles on the truck and it is shifting hard clunk clunk going into second gear and third gear a little bit.

2019 Silverado – same thing. Did the tsb flush about 2k miles ago. Fixed for a while. Now I have a noticable kuh-thunk feeling if I hit the accelerator from a <10 mph roll. It’s going back in asap as I am nearing 36k/3-years.

I have a 2017 GMC Denali (52000 miles) with this exact problem. it will surge a bit when on cruise control

Questions About The GM 8 Speed Transmission Lawsuit? is not counsel or the settlement administrator in this class action investigation. Our goal is to inform owners of these vehicles of the current lawsuit.

This post will be updated as more information is officially announced. Please consider subscribing to this post for critical updates.

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View posts by Christopher
Loves anything with a motor and wheels. Christopher is an internet technology and automotive expert. When he's not at the local autocross event, he can often be found working on one of his cars. He loves nothing more than taking something apart and putting it back together again–better than before.


  1. Christopher
    ChristopherMarch 18, 2022

    Please share your experiences with the GM 8 speed transmission.

  2. Avatar
    MichaelApril 14, 2022

    When accelerating the car shifts hard from 1-2, 2-3, and 3-4. At approx 55 mph the car shudders and feels like you are driving on the rumble strip and continues to do so up to 70 mph. After reaching highway speeds the transmission surges with engine speed fluctuating erratically. Upon deceleration from freeway speeds I have noted, more than once, a violent downshift that the first time it occurred it felt like the car was rear ended by another vehicle. The trans will slip infrequently after it has warmed up. This car is essentially undrivable if you have any concern about safety or reliability. I cannot and will not put my family at risk in this car. I have a 2017 Camaro that has 26xxx miles on it and its a yard ornament. Really hope this is resolved and the car fixed as it should have never left the assembly line with this type of known defect.

    1. Avatar
      GrantJune 19, 2022

      This article resembles almost identically what I am experiencing with the 2018 Cadillac ATS that I unfortunately bought !!

      Dealership has been useless and is in denial of the symptoms I’m experiencing even though warranty still applies.


  3. Avatar
    A LedouxJune 20, 2022

    Same issue in canada, approaching end of warrantee, and the dealership refuses to fix it citing normal operating parameters.

    Disgusted, the issue is infrequent, but sometimes in stop and go traffic the truck lurches forward when slowing to a crawl, its terrible.

    Because of the dealership refusing to fix the issue, nor document it on my file, this will be the last GMC product I buy ever.

    Overpriced piece of junk, and criminal actions from a company that new about the issue and did not disclose to me before purchase.


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