Transmission issues 2020 C8
Burning Brakes
Joined: Sep 2019
Posts: 1,089
Likes: 668
From: Orange County, CA
Sucks to hear a bunch of people have bad transmissions. Pretty terrible quality control if they don't test drive the cars after being built. I guess I got lucky. Mine had 6 miles on it when delivered and there are signs that it was reworked.
7th Gear
Joined: Aug 2021
Posts: 7
Likes: 2
From: Newport Beach, CA
Jeff
1st Gear
Joined: Aug 2021
Posts: 1
Likes: 0
Transmission fail
Our 2020 C8 suddenly started skipping even numbered gears and bucking. We have to wait a week for service as not all “authorized” Chevy dealers have a transmission tech. Unable to drive it and are having it towed to dealer. Second tow for this car, first was frunk issue, car wouldn’t go over 25 mph. Very frustrating!
7th Gear
Joined: Aug 2021
Posts: 7
Likes: 2
From: Newport Beach, CA
Our 2020 C8 suddenly started skipping even numbered gears and bucking. We have to wait a week for service as not all “authorized” Chevy dealers have a transmission tech. Unable to drive it and are having it towed to dealer. Second tow for this car, first was frunk issue, car wouldn’t go over 25 mph. Very frustrating!
7th Gear
Joined: Aug 2021
Posts: 7
Likes: 2
From: Newport Beach, CA
Sorry. But I have no idea what GM's policy is for reusing the returns. And I couldn't find any information regarding the permissibility or legality for using or not being able to use remanufactured parts on new vehicles. My guess is that they may be remanufactured for later, out-of warranty use.
Race Director
Joined: Apr 2003
Posts: 19,348
Likes: 654
From: Tampa, Florida
Intermediate
Joined: Aug 2017
Posts: 43
Likes: 14
From: South Eastern USA
Last November, it was announced that GM obtained a license to build them [DCT] in house at a factory in Canada. My dealer told me my build date was the first week of January. I took delivery the first week of February. So I have no idea where the transmission was built. I just know it failed at 765 miles, and that the dealers are replacing them rather than fixing them. But by moving them in house, it should (should) reduce the problems going forward.
Jeff
Jeff
At 1200 miles, no problems with anything and I've been listening and watching things closely. I do notice that in the V4 mode, and while using the cruise control, the tach dithers while the speedometer indicates a constant speed. Such is not detectable in the V8 mode.
Last edited by TeeH; Oct 7, 2021 at 12:26 AM.
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Drifting
Joined: Jan 2014
Posts: 1,285
Likes: 164
From: MA
Sorry. But I have no idea what GM's policy is for reusing the returns. And I couldn't find any information regarding the permissibility or legality for using or not being able to use remanufactured parts on new vehicles. My guess is that they may be remanufactured for later, out-of warranty use.
Drifting
Joined: Jan 2014
Posts: 1,285
Likes: 164
From: MA
Never get the 1st (or even 2nd) model years of a totally new design vehicle, get those 1st/2nd model years USED @ huge discount after the orginal owner has already made the trips back/forth to the dealer working out the kinks & performing all the TSB's/updates along the way. Or wait until the 3rd model year & beyond when they typically start to get the design totally dialed in.
4th Gear
Joined: Sep 2021
Posts: 4
Likes: 2
C8 Corvette Transmission failure
Just got my new C8 convertible. Car shut down on highway. Would not start or go into neutral. Had it towed back to dealer on a flatbed. WAS TOLD IT NEEDS A NEW TRANSMISSION EVEN THOUGH IT ONLY HAS 250 TOTAL MILES ON IT.!!! Unbelievable, and apparently I'm not the only one.
Instructor
Joined: Oct 2020
Posts: 209
Likes: 43
Just got my new C8 convertible. Car shut down on highway. Would not start or go into neutral. Had it towed back to dealer on a flatbed. WAS TOLD IT NEEDS A NEW TRANSMISSION EVEN THOUGH IT ONLY HAS 250 TOTAL MILES ON IT.!!! Unbelievable, and apparently I'm not the only one.
Last edited by Langang; Sep 29, 2021 at 10:59 PM.
Instructor
Joined: Aug 2021
Posts: 139
Likes: 42
From: Newnan, GA
Just got my new C8 convertible. Car shut down on highway. Would not start or go into neutral. Had it towed back to dealer on a flatbed. WAS TOLD IT NEEDS A NEW TRANSMISSION EVEN THOUGH IT ONLY HAS 250 TOTAL MILES ON IT.!!! Unbelievable, and apparently I'm not the only one.
Melting Slicks
Joined: Jun 2012
Posts: 2,226
Likes: 1,029
From: Thomas Texas
My C8 was built 7/26/21 and the sticker indicates that both the engine and transmission were built in the US.
At 1200 miles, no problems with anything and I've been listening and watching things closely. I do notice that in the V4 mode, and while using the cruise control, the tach dithers while the speedometer indicates a constant speed. Such is not detectable in the V8 mode.
At 1200 miles, no problems with anything and I've been listening and watching things closely. I do notice that in the V4 mode, and while using the cruise control, the tach dithers while the speedometer indicates a constant speed. Such is not detectable in the V8 mode.
Intermediate
Joined: Aug 2017
Posts: 43
Likes: 14
From: South Eastern USA
RussM05, didn't the LT1 and the 8-speed torque converter automatic do this with the torque converter and caused torque converter failure in many of the 8-speed torque converter automatics? I'm going to use the Manual paddle shift mode as much as possible to keep the engine in V8 mode to avoid slipping my DCT clutches. What'd you think?
Melting Slicks
Joined: Jun 2012
Posts: 2,226
Likes: 1,029
From: Thomas Texas
RussM05, didn't the LT1 and the 8-speed torque converter automatic do this with the torque converter and caused torque converter failure in many of the 8-speed torque converter automatics? I'm going to use the Manual paddle shift mode as much as possible to keep the engine in V8 mode to avoid slipping my DCT clutches. What'd you think?
What’s Next
Joined: Dec 2020
Posts: 1,293
Likes: 834
From: Reality
Advanced
Joined: Jul 2020
Posts: 72
Likes: 19
At new owner's school in Nevada, the instructors made mention of three major things to do before tracking a C8. 1: Be sure to add the 2 quarts of fluid to the transmission. They burned up a DCT testing the car. The centrifugal forces uncover the fluid ports and starve the DCT of lubrication. One might think that GM would just add the 2 quarts at the factory. It's a major undertaking if you do it yourself. 2: be sure to have the 4 wheel alignment for track setup. 3: NEVER put the car in the "track mode" unless you're on a track. Why? Tracks are swept daily so there's little or no debris. The suspension in the track mode is considerably stiffer than in other modes. There are no potholes on a track. There is a greater possibility of breaking a rim or damaging the suspension system or just plain sliding off the road if you hit gravel or a pothole. I'm just a messenger here! I only know what Rick Malone and his boys told us...more than once!
Advanced
Joined: Jul 2020
Posts: 72
Likes: 19
Car moves along at 8 MPH with no accelerator input
I'm not losing my mind here! I understand the "hill assist". It's annoying but OK. I note that if I take my foot off of the brakes, the car will trundle along nicely on level ground at about 8MPH in 1st gear. The tach is a comfortable 600RPM and the car just happily goes along. It will also pull nicely uphill if I take my foot off of the brake and "hill assist" isn't engaged. Has anyone else experienced this? This didn't happen with my C7 but it also had a torque converter which the C8 doesn't have. Ideas folks?
Drifting
Joined: Mar 2020
Posts: 1,568
Likes: 1,026
From: 31 hours East of Peoria, AZ
I'm not losing my mind here! I understand the "hill assist". It's annoying but OK. I note that if I take my foot off of the brakes, the car will trundle along nicely on level ground at about 8MPH in 1st gear. The tach is a comfortable 600RPM and the car just happily goes along. It will also pull nicely uphill if I take my foot off of the brake and "hill assist" isn't engaged. Has anyone else experienced this? This didn't happen with my C7 but it also had a torque converter which the C8 doesn't have. Ideas folks?
Caution Spinning the tires or holding the vehicle in one place on a hill using only the accelerator pedal may damage the transmission. The repair will not be covered by the vehicle warranty. If the vehicle is stuck, do not spin the tires. When stopping on a hill, use the brakes to hold the vehicle in place