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2018 CT6 8 speed transmission problems

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    I have had my 2018 CT6 Luxury for about a year. It has the 8 speed transmission that gives choppy shifts when the motor is cold. This is apparently very common and the dealer has told me that since it shows no codes on the diagnostic, nothing can be done. Apparently such a common problem, that the transmission was redesigned in 2019 to make the 10 speed transmission. Does anyone have comments? Any thoughts of a class action suit?


    General Motors had significant issues with the 8-spd transmissions installed in Corvettes and Camaro vehicles. A friend of mine recently bough a 2015 Corvette 8-spd (7K miles) and his car started “shuddering” from the transmission. He found there is a class action lawsuit from issues with this transmission. Records showed his car had the torque converter replaced in 2016 trying to correct the problem. Since then GM has found it was the fluid causing the problem as it seemed to have an affinity for attracting moisture. He had the dealer flush the transmission 3 times and refill with the new fluid designed to correct this issue. He’s told me it seems perfect now, but this was a $600 repair.


    Thanks mjdart
    I will contact my dealer with the suggestion. Car was a cpo so still under the last year of warranty.


    I have a 2019 ct6 cadillac & I feel like my transmission jumps also. The dealership said nothing was wrong with it. Also the auto start & stop system should be smooth. It makes my car jump hard when it starts back up.


    I have the 2017 CT6 platinum, my only disappointment with this car is the transmission. I got it used with 20k miles.
    I noticed shifting issues when I started to drive it. I was still under warranty for the drivetrain so I had my local dealer
    check it out. After a number of iterations, ended up replacing the transmission. As I have researched this this transmission
    has issues with design. The poor shifts are usually 1-2. It doesnt do it all the time but more than I would like. I live with it because
    i really love the car, 3.0TT, 34 speakers, active suspension, a black on black paint and interior. The 20 inch wheels, I get 30mph on
    he highway.


    I had fluid changed. Still sometimes rough shift 1 to 2.

Viewing 6 posts - 1 through 6 (of 6 total)
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