GM 8-speed Transmission Problems Could Prompt Class Action Lawsuit

General Motors is in the news again regarding a possible class action lawsuit. Autoblog.com recently released an article that talks about problems associated with 2015-’18 8l90 and 8l45 GM 8-speed transmissions. According to Autoblog.com, a lawsuit was posted to ClassAction.org and spotted by GM Authority. A complaint has already been filled with the National Highway Traffic Saftey Administration with some reporting damage to their vehicles.

2015 Hydra-Matic 8L90 (M5U) Eight Speed RWD Automatic Transmission for Chevrolet Silverado, GMC Sierra, GMC Yukon and Yukon XL, Cadillac Escalade and Escalade ESV

The complaint reads, “These transmissions have a common defect. Drivers attempting to accelerate or decelerate their cars feel a hesitation, followed by a significant shake, shudder, jerk, clunk, or hard shift when the vehicle’s automatic transmission changes gears. Said shudder, shake and hesitation also occurs while the subject vehicles are accelerated in a single gear, and not actively shifting gears. Drivers have reported that the shift is sometimes so violent, they feel as though they have been hit by another vehicle. In fact, one purchaser reported that the transmission shifted from reverse to drive so harshly that he almost drove through his garage door.”

On page 2 of the 85-page document talks about that GM has known about the transmission defect for years and states, “Since 2015, GM has issued thirteen versions of a technical service bulletin, or TSB, related to this shifting issue alone. A TSB is an alert to dealerships, informing them of a potential problem in a GM product and advising them how to address the problem when customers complain to GM dealerships. The TSBs related to the transmission issue have advised dealerships to, among other things: complete the “clutch drive learn procedure,” replace the valve body, replace the entire transmission, flush the cooler lines and cooler, remove debris from and clean the transmission pan, replace the transmission filter, replace the transmission fluid, and flush the transmission.”

A consumer in Middleville, MI states in the document, “The 8-speed transmission bucks, hesitates, lurches forward, clunks while starting acceleration or coming to a stop. I try to keep a big gap between my truck and cars in front of me at stop signs because it randomly lurches forward and I have almost bumped cars in front of me. The consumer continues, “I am past my warranty so, the dealer says any cost is my responsibility.”

Here is a list of vehicles that could be affected:

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

While it’s pretty obvious that some of the 8-speed transmissions have problems, an immediate solution is not as apparent. We hope that GM can get this problem sorted out soon. For a look at the full class action complaint click here.

About the author

Brian Havins

A gearhead for life, Brian is obsessed with all things fast. Banging gears, turning wrenches, and praying while spraying are just a few of his favorite things.
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