GM 10-Speed Transmission Class Action Lawsuit, Did Your Truck or SUV Shake, Shift Violently, or Lock Up?

General Motors is facing a class action lawsuit filed on April 13, 2026, in the U.S. District Court for the Northern District of California, San Francisco Division, alleging the automaker sold trucks and SUVs with defective 10-speed automatic transmissions that shake, hesitate, and lock up their wheels without warning. Plaintiffs include Napa Valley G Experience LLC, Juan Morales, and Ruben Smith, and the proposed class covers California consumers who purchased or leased certain GMC Sierra, Chevrolet Suburban, and GMC Yukon vehicles with the affected transmissions. No settlement has been reached, and no claim form is currently available.

Quick Facts: GM 10-Speed Transmission Lawsuit 2026

Field	Detail
Lawsuit Filed	April 13, 2026
Defendant	General Motors LLC
Case Name	Napa Valley G Experience LLC et al. v. General Motors LLC
Alleged Violation	Product defect / concealment — breach of implied warranty and consumer protection laws
Who Is Affected	California purchasers and lessees of certain GMC Sierra, Chevrolet Suburban, and GMC Yukon vehicles with 10-speed transmissions
Current Court Stage	Early litigation — recently filed, no class certification yet
Court & Jurisdiction	U.S. District Court for the Northern District of California, San Francisco Division
Lead Law Firm	TBD — not yet publicly confirmed in available court filings
Next Hearing Date	TBD — not yet scheduled
Official Case Website	TBD — none established yet
Last Updated	May 5, 2026

What Is the GM 10-Speed Transmission Lawsuit About? Napa Valley G Experience LLC et al. v. General Motors LLC

GM’s 10L series includes the 10L60, 10L80, 10L90, and 10L1000 transmissions. GM co-developed the 10-speed platform with Ford starting in 2013 and rolled it out broadly across its truck and SUV lineup, marketing it as breakthrough technology delivering smooth shifting, high efficiency, and strong performance.

The complaint identifies three main failure categories: harsh noises and sensations during shifts, unreliable acceleration and deceleration, and momentary wheel lockup on certain downshifts. Plaintiffs attribute those symptoms to instability in hydraulic pressure control and clutch timing — specifically valve body wear, torque converter contamination, and inadequate software calibration.

Napa Valley G Experience LLC alleged it purchased a 2022 Chevrolet Suburban that exhibited shaking, shuddering, and harsh mechanical noises. California resident Juan Morales claimed he purchased a 2021 GMC Sierra 1500 Crew Cab Denali that required a full transmission replacement after multiple dealer visits failed to resolve harsh, erratic shifting. If your vehicle threw you around during a highway merge, lurched unexpectedly while towing, or triggered a check engine light after a software update, you are exactly the driver this defective product lawsuit is about.

The lawsuit alleges violations of California consumer protection law and breach of implied warranty — the legal promise that a product will work as reasonably expected. For legal context on how these product liability claims work, see our GM class action lawsuits overview covering the LC9 engine, Shift to Park, and 10-speed transmission cases.

Are You Part of the GM 10-Speed Transmission Class Action?

This is the section that matters most to you. Here is how to know if this lawsuit includes you.

You may be part of this class if:

• You purchased or leased a new GMC Sierra, Chevrolet Suburban, or GMC Yukon in California
• Your vehicle came equipped with a 10-speed automatic transmission (10L60, 10L80, 10L90, or 10L1000)
• You experienced any of the following: harsh or violent shifting, shuddering, hesitation when accelerating, wheel lockup, transmission dropping into “limp home” mode, or a service engine light tied to transmission codes
• Your vehicle is a model year 2020–2024 and continues to show failures despite receiving the NHTSA recall software update
• You took your vehicle to a GM dealer one or more times without a permanent fix

You are likely NOT included if:

• You purchased your vehicle outside California (the proposed class is currently limited to California consumers — other states may follow)
• Your vehicle does not have a 10-speed automatic transmission
• You have not experienced any of the transmission symptoms described in the complaint

Note on the prior 8-speed lawsuit: A separate, older class action over GM’s 8-speed transmissions (8L45/8L90) covering 2015–2019 models was decertified by the Sixth U.S. Circuit Court of Appeals in June 2025, which ruled that differences among the 800,000 vehicle owners were too great to justify a single class. That case is now remanded back to district court. If you own a 2015–2019 GM vehicle with an 8-speed, that is a separate matter — speak with a consumer rights lawyer about your options.

What Are GM Plaintiffs Seeking in This Lawsuit?

The plaintiffs are not seeking a small software patch. They want the court to hold GM accountable for selling vehicles with a defect the company allegedly knew about long before buyers drove off the lot.

The complaint claims that GM’s two safety recalls — NHTSA Recall 24V-797 covering 461,839 diesel-powered vehicles and NHTSA Recall 25V-148 covering 90,081 gasoline-powered vehicles — do not constitute genuine repairs. Both recalls offer only a software update that locks the transmission into fifth gear when the system detects excessive valve body wear, a condition mechanics call “limp home” mode.

The plaintiffs point to continued failures in 2023 and 2024 model year Escalades, Suburbans, Sierras, and Silverados — some with as few as 1,100 miles on the odometer — as proof that the recalls are underinclusive and the underlying defect remains unaddressed.

Aftermarket supplier Next Gen Drivetrain identified crosslinks in the valve body as the root cause of the wheel lockup and developed replacement kits, warning GM about what it called an “extreme safety problem.” Plaintiffs claim GM initially refused to purchase the parts, though roughly 60 to 70 GM dealers allegedly independently opened wholesale accounts with Next Gen and bought the kits on their own.

Related article: Hyundai, Kia, and Genesis ICCU Class Action Lawsuit, Recalls Failed Are You Still at Risk? Ioniq 5 & EV6 Still Losing Power

The plaintiffs are seeking compensation for damages including the cost of repairs, diminished vehicle value, out-of-pocket expenses, and injunctive relief requiring GM to fix the defect properly — not just patch the software. No specific dollar amount has been filed for the class as a whole at this stage. For a comparable case involving another automaker’s transmission defect, see our coverage of the Toyota UA80 transmission lawsuit.

What Should You Do If Your GM Truck or SUV Has Transmission Problems?

You do not need to file a lawsuit today. Most class members are automatically included in the proposed class once it is certified — you do not need to take any action right now to preserve your place. But there are smart steps to take now that will matter later.

Document everything starting today:

• Save every dealer repair order, even if the technician wrote “no fault found”
• Write down the date, speed, and conditions every time your transmission shifts violently, shudders, or triggers a warning light
• Keep any correspondence with GM Customer Service — phone call logs, emails, case numbers
• If your vehicle was placed in limp home mode after the recall software update, document that specifically — it is central to the complaint
• Pull your vehicle’s NHTSA recall status at nhtsa.gov using your VIN to confirm which recalls apply to your vehicle

If you want to pursue an individual claim rather than wait for the class action, consult a class action lawsuit attorney directly. Many offer a free legal consultation and can advise whether a lemon law claim in California — which can deliver faster, larger individual recovery than a class settlement — is a better path for your situation.

Monitor this case through the U.S. District Court for the Northern District of California’s public docket for scheduling orders, class certification rulings, and any settlement announcements.

GM 10-Speed Transmission Class Action Lawsuit Timeline

Milestone	Date
NHTSA Recall 24V-797 (461,839 diesel vehicles)	October 24, 2024
NHTSA Recall 25V-148 (90,081 gasoline vehicles)	March 6, 2025
Class Action Filed (N.D. Cal., San Francisco Division)	April 13, 2026
Class Certification Motion	TBD — not yet filed
Next Scheduled Hearing	TBD — not yet scheduled
Expected Settlement Timeline	TBD — early litigation stage; class certification typically takes 12–24 months after filing

Frequently Asked Questions

Is there a class action lawsuit against GM for 10-speed transmission problems?

Yes. Napa Valley G Experience LLC et al. v. General Motors LLC was filed on April 13, 2026, in the U.S. District Court for the Northern District of California. The lawsuit covers California purchasers and lessees of certain GMC Sierra, Chevrolet Suburban, and GMC Yukon vehicles with 10-speed automatic transmissions.

Do I need to do anything right now to be part of the GM transmission lawsuit?

No immediate action is required. If the court certifies a class, California residents who purchased or leased qualifying vehicles will typically be included automatically. Save your repair records and document every transmission symptom you experience — that documentation is what turns a general class member into a strong one.

When will the GM 10-speed transmission lawsuit settle?

There is no settlement yet. The case was filed in April 2026 and is in early litigation. Class certification alone typically takes one to two years. A settlement, if reached, would come after that. No payout timeline or dollar amount exists at this stage.

Can I file my own lawsuit against GM instead of waiting for the class action?

Yes. You can pursue an individual lemon law claim or a separate consumer protection action independent of this class action. California’s lemon law in particular can provide faster and larger individual recovery than waiting for a class settlement. Speak with a product liability attorney who handles auto defect cases for a case-specific evaluation.

How will I know if the GM transmission lawsuit settles?

When a settlement is reached, the court will require GM to notify affected class members — typically by mail using vehicle registration records. You can also monitor the Northern District of California’s PACER docket or check back here at AllAboutLawyer.com for updates.

My vehicle already got the recall software update — does that affect my eligibility?

Receiving the recall does not disqualify you. The complaint specifically argues that the software update is not a genuine repair and that vehicles continue to fail after receiving it. The plaintiffs contend neither recall constitutes a genuine repair and that failures continue in newer model year vehicles, some with as few as 1,100 miles on the odometer. If your truck shifted erratically or triggered limp home mode after the recall, document that — it may strengthen your position.

What transmission problem caused GM to issue the recalls in the first place?

NHTSA’s official recall report states that excessive wear in a control valve within the transmission was causing harsh downshifting and, in rare cases, a momentary rear wheel lockup. GM acknowledged 1,888 field reports of the lockup condition, along with 11 incidents in which vehicles veered off roadways and three minor injuries.

Sources & References

• Napa Valley G Experience LLC et al. v. General Motors LLC — U.S. District Court for the Northern District of California, San Francisco Division (filed April 13, 2026)
• NHTSA Recall Report 24V-797 — static.nhtsa.gov
• NHTSA Recall Notice 24V-797 — nhtsa.gov
• NHTSA Recall Report 26V085 — static.nhtsa.gov

Prepared by the AllAboutLawyer.com Editorial Team and reviewed for factual accuracy against official NHTSA recall reports and available court filing information on May 5, 2026. Last Updated: May 5, 2026

Disclaimer: This article is for informational purposes only and does not constitute legal advice. Legal claims and outcomes depend on specific facts and applicable law. For advice regarding a particular situation, consult a qualified attorney.