Federal Judge Consolidates Class-Action Lawsuits Over GM’s 8-Speed Automatic Transmission


Federal Judge Consolidates Class-Action Lawsuits Over GM's 8-Speed Automatic Transmission

Photo Credit: CorvetteImages.com

The eight-speed automatic transmissions in several General Motors vehicles, including five model years during the C7 Corvette era, have been the subject of five separate class-action lawsuits claiming defects.

Now, Michigan Judge David M. Lawson has consolidated the five suits and also dismissed two claims – one for implied warranty for all plaintiffs that fall under the laws of Alabama, Arizona, Connecticut, Idaho, Kentucky, North Carolina, Tennessee, Washington, and Wisconsin and another for one plaintiff who claimed class-wide monetary damages under the Colorado Consumer Protection Act.

The suits allege that GM’s 8L45E and 8L90 automatic transmissions can cause slipping gears, shifting into gear aggressively, shuddering or jerking, delayed acceleration, and trouble slowing down. We owned a 2016 Camaro SS for four years and experienced many of these problems firsthand ourselves.

GM argues that because all these transmissions experience these problems, they are caused by a design defect and the suits should be dismissed because GM’s express warranty only covers defects in materials and workmanship.

Other allegations in the suit can proceed, the judge ruled, including certain other claims related to implied warranty. Lawson also noted that the complaints could be consistent with either materials/workmanship defects or a design defect. He also allowed claims to continue that GM was aware of the transmission issues before the vehicles were sold, saying “plausible inferences may be drawn that GM had substantial knowledge about the looming problems with its new transmissions before any of the plaintiffs’ purchases were made.”

The affected Corvettes include 2015-19 models. The first year of the C7 generation featured a six-speed automatic transmission that is not included in the suits.

Other GM vehicles affected include:

  • 2015-2017 Cadillac Escalade
  • 2015-2017 Cadillac Escalade ESV
  • 2016-2019 Cadillac ATS
  • 2016-2019 Cadillac ATS-V
  • 2016-2019 Cadillac CTS
  • 2016-2019 Cadillac CTS-V
  • 2016-2019 Cadillac CT6
  • 2015-2019 Chevrolet Silverado
  • 2017-2019 Chevrolet Colorado
  • 2016-2019 Chevrolet Camaro
  • 2017-2019 GMC Canyon
  • 2015-2019 GMC Sierra
  • 2015-2019 GMC Yukon
  • 2015-2019 GMC Yukon XL
  • 2015-2017 GMC Yukon Denali
  • 2015-2017 GMC Yukon Denali XL


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  1. That eight speed transmission is pure junk! I’ve seen not one, but two fail back to back on two different C7 Z’s. The owner bought another C7 ZO6 this time with seven speed manual and has never had a problem with it. GM use to build some incredibly strong and reliable transmissions, even Rolls Royce used the TH400 back in the day.

  2. Kenneth Gutwein, every Corvette I own has a manual in it. More fun to drive and much better reliability too. Another reason why many people won’t buy a C8 since it has a stand alone 8 speed dct.

  3. Question, Is it possible to change the 8 speed auto in a C7 to the 8 speed auto that’s in the C8?

  4. I wonder how many years GM had truly trouble free vehicles of any category? Like, 100K miles before showing mechanical issues in the drivetrain . Not many.

  5. This doesn’t surprise me the least…a manufacturer that cannot take responsibility for junk. I have had similar issues with my 2006 impala LT since new and I know other people who have had the same issues. I also know someone who had a Chevy Traverse that had to have the transmission partially rebuilt twice in 40000 miles since it rolled off the showroom floor. GM will never admit to using cheap internal parts in order to cut costs…give me the old Turbo 350 transmission any day…that’s when stuff was built right…

  6. Any chance I can get a new one from the dealership after they fix the issue? I would love to get a new transmission for free courtesy of GM. It would definitely be the right thing to do.

  7. The two flushes and refill of the automatic eight speed did help, but I was left with a vibration in the drive line. Car was at the dealer for eight days and they determined it was the factory belts and replaced them with gates belts costing me eight hundred dollars. 7000 miles on car and not covered by driveline warrantee. This will be my seventh and last corvette. A;so cracked windshield witch I will save for another blog.


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