There is a class action law suit being initiated against GM for these faulty 8-speeds:
https://topclassactions.com/lawsuit-settlements/consumer-products/auto-news/869062-gm-class-action-alleges-hard-shift-transmission-defect/
I own a 2016 Sierra SLT that I purchased brand new. I've had these problems since the truck was new. Took the truck back to GMC multiple times and the problem was never fixed.
I contacted Cohen Milstein by email and requested I be listed in the lawsuit. They said someone will contact me shortly to gather more information about my experience.
If you are having problems with your 8-speed, I suggest you reach out:
Jamie Galucci @
[email protected]
Paralegal to Steven G. Calamusa, Esq.
4114 Northlake Blvd, Palm Beach Gardens, FL 33410
office: (561) 799-5070 fax: (561) 799-5040
www.fortheinjured.com
*************UPDATE*********************
Here is a link to the class action lawsuit
