General Motors faces a new class-action lawsuit after owners claimed the automaker’s 8-speed automatic transmission houses a major defect. Per the information posted to Classaction.org, drivers have experienced violent shakes, jerks, or a “hard shift” when selecting a gear with the automatic transmission.
The information also says 13 technical service bulletins have been filed about 8-speed automatic transmission problems, though none of them have remedied the problem absolutely.
The technical name for this transmission is either the 8L90 or 8L45 automatic transmission, which is found in numerous GM vehicles. The transmission pairs to cars on a rear-wheel-drive architecture, meaning owners of GM’s sports cars, luxury sedans, trucks, and SUVs have the 8-speed automatic transmission in question.
Specifically, the transmission is found in:
- 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
- 2017-2019 GMC Canyon.
The problem is most common when a driver accelerates of decelerates and the transmission moves to shift a gear. Drivers reported a hesitation, then a shudder or jerk with the gear change. However, it’s not exclusive to gear changes as some owners reported the issue within a single gear. According to the information compiled so far, some drivers said the event has been so violent it felt like another car had hit them.
One owner reported that moving from the “reverse” to “drive” gear was so violent that the car nearly drove through a garage door.
It’s worth noting the NHTSA has also received numerous complaints about the transmission found in the number of GM vehicles. The lawsuit claims the issue’s source is the torque converter, which may be exposed to undue friction. Eventually, the gears may not function properly as metal shavings move throughout the transmission. This is not a definite conclusion, but an alleged issue in the lawsuit. One NHTSA complaint does cite a failed torque converter after 16,000 miles in a GMC Canyon.