GM Transmission Lawsuit: 8-Speed and 10-Speed Class Actions and Recalls

The GM transmission lawsuit landscape has two active fronts: a long-running class action over 8-speed transmissions in roughly 800,000 Chevrolet, GMC, and Cadillac vehicles from 2015–2019, and a newer class action filed in April 2026 over 10-speed transmissions across a wider range of models. In June 2025, the Sixth Circuit Court of Appeals decertified the main 8-speed class in a 9-7 en banc decision, meaning affected owners currently have to pursue claims individually or through smaller companion cases still working their way through court.

What Owners Are Complaining About

The 8-speed complaints center on GM’s Hydra-Matic 8L90 and 8L45 transmissions installed beginning in the 2015 model year. Owners report a distinctive shudder that feels like driving over rumble strips, typically between 25 and 80 mph under light acceleration and most commonly around 40–50 mph.¹ The condition became widely known as the “Chevy Shake.” Beyond the shudder, owners describe harsh upshifts and downshifts, slipping between gears, delayed engagement, and lurching some plaintiffs compared to being rear-ended.²

The 8-speed litigation covers 2015–2019 model-year vehicles across three brands:

Chevrolet Silverado (2015–2019), Colorado (2017–2019), Corvette (2015–2019), and Camaro (2016–2019).
GMC Sierra (2015–2019), Yukon, Yukon XL, and Yukon Denali XL (2015–2019), and Canyon (2017–2019).
Cadillac Escalade and Escalade ESV (2015–2019), and ATS, ATS-V, CTS, CTS-V, and CT6 (2016–2019).³

The 10-speed complaints cover a different, broader group of vehicles and allege violent or erratic shifting, delayed acceleration, and complete loss of propulsion.⁴

The 8-Speed Class Action and Its Decertification

Speerly et al. v. General Motors, LLC (Case No. 19-cv-11044) was filed in August 2019 in the U.S. District Court for the Eastern District of Michigan before Judge David M. Lawson.⁵ Plaintiffs allege GM knew the transmissions were defective before selling the vehicles and concealed the problems despite issuing at least 13 technical service bulletins to dealers.⁶ The complaint also accuses GM of instructing dealerships to tell customers that harsh shifting was “normal” or “characteristic” of the transmission.⁷

On March 20, 2023, Judge Lawson certified 26 statewide subclasses covering roughly 800,000 vehicle owners and 59 state-law claims, including consumer protection, warranty, and fraud theories.⁵ A three-judge Sixth Circuit panel affirmed that certification on August 28, 2024, and rejected GM’s argument that unnamed class members were bound by arbitration clauses, finding the company had waived arbitration after more than two years of litigation.⁸

Then on June 27, 2025, the full Sixth Circuit reheard the case en banc and reversed. By a 9-7 vote, the court vacated the class certification and sent the case back to Judge Lawson.⁹ Chief Judge Jeffrey Sutton, writing for the majority, held that the district court had not conducted the rigorous, element-by-element analysis Rule 23 requires. Lumping 59 separate state-law claims under a single “defect” concept did not show that one common question could resolve issues central to every claim, and applying laws from 26 different states in one proceeding would be unworkable.¹⁰ The majority also criticized combining two distinct defect theories, transmission shudder and harsh shifting, into one class, and held that GM’s arbitration waiver as to the named plaintiffs did not extend to unnamed class members before certification.

Judge Karen Nelson Moore, joined by six colleagues, dissented. She wrote that plaintiffs had identified two universal defects capable of class-wide resolution and that the majority effectively required a trial-on-the-merits analysis at the certification stage.¹⁰

Related 8-Speed Cases Still Alive

Decertification of Speerly did not end the 8-speed litigation. A second class action, Ulrich et al. v. General Motors (No. 2:24-cv-11007), was filed April 17, 2024, on behalf of consumers in ten states not covered by Speerly: California, Connecticut, Indiana, Iowa, Massachusetts, Missouri, North Dakota, Oregon, Rhode Island, and South Dakota. The Ulrich plaintiffs allege GM knew as early as 2018 about a transmission fluid flush procedure called “Mod1a” that could address the shudder but instead of recalling roughly two million affected vehicles limited the fix to unsold Cadillacs and trucks in certain states, performing it only for customers under warranty who specifically complained.¹¹

In February 2025, Judge Lawson allowed most Ulrich counts to survive GM’s motion to dismiss, dismissing the nationwide unjust-enrichment and fraudulent-omission claims without prejudice and one Oregon consumer-protection claim with prejudice.¹² In June 2025, the court also denied GM’s motion to compel arbitration, ruling the dealership purchase agreement’s arbitration clause did not cover GM because the manufacturer was not a party to those contracts.¹³

Two more consolidated cases share plaintiff leadership with Speerly: Harper et al. v. General Motors (No. 2:21-cv-12907) and Helms et al. v. General Motors (No. 2:22-cv-10783). Fact and expert discovery are ongoing as of mid-2026.¹⁴

The 10-Speed Class Action

A separate lawsuit targets GM’s 10-speed automatic, which the company co-developed with Ford. Napa Valley G Experience LLC et al. v. General Motors (Case No. 3:26-cv-03148) was filed in April 2026 in the U.S. District Court for the Northern District of California. Plaintiffs allege GM knowingly sold vehicles with 10-speed transmissions prone to violent or erratic shifting, delayed acceleration, and complete loss of propulsion.⁴

The 10-speed shows up as standard or optional equipment across a wide lineup, including the 2018–2025 Cadillac Escalade, 2021–2025 Chevrolet Tahoe and Suburban, 2019–2022 Chevrolet Silverado, 2019–present GMC Sierra, and 2020–2025 GMC Yukon Denali, among others.¹⁵ GM had not publicly responded to the California lawsuit as of mid-2026.⁴

Recalls to Check

Separate from the lawsuits, GM has issued several transmission-related safety recalls that come with a free fix.

In October 2024, GM recalled approximately 462,000 pickups and SUVs with 10-speed transmissions and Duramax turbo-diesel engines because transmission control valves were susceptible to excessive wear that could cause harsh shifting or, in rare cases, rear-wheel lock-up during downshifts. The affected vehicles include 2020–2022 Silverado and Sierra 1500, 2500, and 3500 trucks along with 2021 Tahoe, Suburban, Yukon, Yukon XL, Escalade, and Escalade ESV models. A GM investigator identified 1,888 field reports of rear-wheel lockups filed between January 2020 and August 2024.¹⁶

In February 2025, GM added about 90,000 more vehicles for the same control valve problem: the 2020–2021 Cadillac CT4, CT5, and CT6, and the 2020–2022 Chevrolet Camaro. One accident had been reported involving a momentary wheel lock-up.¹⁷ A third recall in February 2026 covered 43,732 full-size 2022 SUVs (Tahoe, Suburban, Yukon, Yukon XL, Escalade, and Escalade ESV), with 13 field reports of rear-wheel lockup between late 2023 and October 2025. Across all three recalls, the remedy is a software update to the transmission control module that monitors valve wear and limits the vehicle to fifth gear if degradation is detected.¹⁸

GM also released special coverage in late 2024 extending transmission repair protection to 15 years or 150,000 miles for certain 2020–2022 trucks and SUVs covered by the earlier recalls, for qualifying repair orders placed after November 26, 2024.¹⁸ A separate November 2024 recall covered 77,824 Chevrolet Express and GMC Savana vans (2022–2023 model years) with 8-speed transmissions for a software calibration error that could cause harsh shifting, reduced power, or momentary rear-wheel lock-up.¹⁹

What to Do If You Own an Affected Vehicle

With the Speerly class decertified, the 8-speed case no longer functions as one large group lawsuit. Owners of 2015–2019 vehicles listed above currently have to pursue claims individually or wait to see whether plaintiffs’ counsel succeed in certifying smaller subclasses when the case returns to Judge Lawson.⁶ Owners in the ten states covered by Ulrich, and any owners whose vehicles fall within Harper or Helms, remain part of active litigation in discovery.¹⁴

For the 10-speed lawsuit filed in California, owners may want to weigh whether to remain in the putative class or opt out to preserve individual rights under state lemon laws, depending on repair history and the severity of the problems.¹⁵

Anyone driving a vehicle covered by the 10-speed control valve recalls should contact a GM dealership to have the free software update performed. Owners of 2020–2022 trucks and SUVs on the recall lists may also qualify for the special coverage extending transmission repair protection to 15 years or 150,000 miles.¹⁸

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Berger Montague. Speerly, et al. v. General Motors, LLC
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NBC News. General Motors Vehicles Recalled for Transmission Problem That Could Cause Wheels to Lock
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19
NHTSA. Recall No. 24V-839