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Plaintiffs Gave General Motors a Win in the 8-Speed Transmission Lawsuit

The plaintiffs haven't been able to explain delays and keep trying to make too many changes.

by Allison Barfield

Published on December 11, 2025 9:45 am

2 min read

Uh oh, plaintiffs involved in a class-action lawsuit may have shot themselves in the foot. The case is related to two General Motors eight-speed automatic transmissions for alleged defects. But apparently, the plaintiffs showed a lack of diligence.

Plaintiffs face trouble in the General Motors eight-speed transmission lawsuit

General Motors has been battling an eight-speed automatic transmission lawsuit for years. Allegedly, the 8L90 and 8L45 transmissions are defective.

The plaintiffs shared that they were prone to hesitating, jerking, surging, lurching, and acceleration problems. Plus, they had harsh gear shifts.

On top of that, going to General Motors reportedly didn’t help, as the technicians claim the vehicles were performing as designed. Also, the plaintiffs allege that the transmissions were replaced equally as defective units.

Models involved in this mess include:

2019 – 2022 Chevrolet Camaro
2019 – 2022 Chevy Colorado
2019 – 2022 Chevy Silverado
2019 Chevy Corvette
2019 Cadillac ATS
2019 Cadillac ATS-V
2019 Cadillac CTS
2019 Cadillac CT6
2019 Cadillac CTS-V
2019 – 2022 GMC Canyon
2019 – 2022 GMC Sierra
However, the judge allowed the plaintiffs to file an amended lawsuit to add customers from nine other states and the spouses of existing plaintiffs. Then one lawsuit was decertified.

Also, according to CarComplaints, two plaintiffs never began arbitration, and one of them never told the judge that they sold their vehicle.

General Motors argues that the plaintiffs shouldn’t be substituted, but they were allowed to file a second amended class action. But a second amendment was already filed, so it was really a third amended.

Then General Motors claimed they waited too long to substitute the plaintiffs and never explained the reasoning for the delay, and the judge agreed. The judge also agreed that the plaintiffs showed a lack of diligence and denied a motion to expand model years.

Also, the judge was admittedly a bit confused. But this all seems to play out in General Motors’ favor for now.

Staff Writer

Allison Barfield

Allison Barfield is a MotorBiscuit Staff Writer and covers all things Trucks and SUVs. She covers Stellantis regularly, including Dodge, Ram, and Jeep vehicles. Allison graduated from the University of South Carolina with a degree in Media Arts. She’s spent the last several years testing new cars for MotorBiscuit and writing about their pros and cons. Her dog, Bruce, often joins her on test drives.

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