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DCT has no even gears (2, 4, 6, 8 missing)

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  • DCT has no even gears (2, 4, 6, 8 missing)

    While out for an enjoyable drive today, with nothing out of normal in terms of driving style, I lost access to the even gears (2,4,6,8).

    I first noticed it while I was accelerating and the car wasn't shifting into 2nd (in Drive mode, not Manual mode), but was staying in 1st gear at high RPM. Paddle shifting to get 2nd gear was unresponsive. I pressed the M button to switch into Manual mode, and I was then able to shift into 3rd gear and then later into 5th gear.

    No even gears were available.

    A CEL then came on, and there was a warning that creep mode (?) was disabled.

    I pulled into a parking lot, shut off the car, waited 10 seconds and restarted it. The shifting problem remained.

    The car remained drivable, and I was able to make it home (~3 miles) without any issue, beyond poor shifting.

    The car has never had any issues until now (~5100 miles).

    I know that the DCT transmission design involves odd gears on one shaft and even gears on another, and I do recall hearing of people losing even gears with DCTs before, although I couldn't find anything on the web regarding C8s having this transmission issue.

    Any of this sound familiar to the other C8 owners on the forum?
    Last edited by Mobius; 04-08-2021, 11:40 AM.
    My C8:
    '20 Elkhart Lake Blue 2LT Coupe, Natural Interior, GT2 Two-Tone Seats, Performance Exhaust, Front Lift, Carbon Flash Wheels, Engine Appearance Package 2000 Status December 27, 2019; 3000 Status January 2, 2020; 3400 Status March 10, 2020;TPW March 16, 2020; Built June 4th, 2020 (COVID-19); Delivery July 1, 2020

    Current Vettes:
    '68 Lemans Blue 327/350 Convertible
    '91 Turquoise Convertible with Hardtop
    '14 Lime Rock Green 2LT Convertible, Black Top, Kalahari, 7-Speed, Performance Exhaust

  • #2
    You might soon have a new DCT (or maybe not). The fact that it was fine until 5100 miles doesn't give me much comfort (~4500 miles).

    https://www.midenginecorvetteforum.c...smission-gears
    Last edited by jackfrostpdx; 04-06-2021, 04:06 PM.

    Comment


    • #3
      Mobius, we are all sorry. If I remember correctly this was a DCT clutch that needed replacing for one owner. Hopefully yours would be way simpler like a fluid drain, canister change and refill, but if not as jackfrostpdx noted, GM has not been messing around with DCT problems, but replacing with brand new transmissions.

      Thanks for keeping us posted as this gets resolved.
      GBA Black; HTO Twilight/Tension interior; Z51 & Mag Ride; E60 lift; 5VM visible carbon fiber package; 5ZZ high wing; FA5 interior vis CF; ZZ3 engine appearance; 3LT; Q8T Spectra Gray Tridents; J6N Edge Red Calipers; SNG Edge Red Hashmarks; VQK Splash Guards; RCC Edge Red engine cover; VJR illuminated sill plates. Lifetime, annual contributors, and 23 year members of National Corvette Museum. Home is the beautiful Pacific Northwest.

      Comment


      • #4
        Originally posted by jackfrostpdx View Post
        You might soon have a new DCT (or maybe not). The fact that it was fine until 5100 miles doesn't give me much comfort (~4500 miles).

        https://www.midenginecorvetteforum.c...smission-gears
        Excellent and helpful thread - thanks!
        My C8:
        '20 Elkhart Lake Blue 2LT Coupe, Natural Interior, GT2 Two-Tone Seats, Performance Exhaust, Front Lift, Carbon Flash Wheels, Engine Appearance Package 2000 Status December 27, 2019; 3000 Status January 2, 2020; 3400 Status March 10, 2020;TPW March 16, 2020; Built June 4th, 2020 (COVID-19); Delivery July 1, 2020

        Current Vettes:
        '68 Lemans Blue 327/350 Convertible
        '91 Turquoise Convertible with Hardtop
        '14 Lime Rock Green 2LT Convertible, Black Top, Kalahari, 7-Speed, Performance Exhaust

        Comment


        • #5
          Originally posted by John View Post
          Thanks for keeping us posted as this gets resolved.
          Will do!

          Funny, this is the first real issue I've had with the car.

          It looks like I'll have to "settle" for the C7 convertible while the C8 gets sorted out.
          My C8:
          '20 Elkhart Lake Blue 2LT Coupe, Natural Interior, GT2 Two-Tone Seats, Performance Exhaust, Front Lift, Carbon Flash Wheels, Engine Appearance Package 2000 Status December 27, 2019; 3000 Status January 2, 2020; 3400 Status March 10, 2020;TPW March 16, 2020; Built June 4th, 2020 (COVID-19); Delivery July 1, 2020

          Current Vettes:
          '68 Lemans Blue 327/350 Convertible
          '91 Turquoise Convertible with Hardtop
          '14 Lime Rock Green 2LT Convertible, Black Top, Kalahari, 7-Speed, Performance Exhaust

          Comment


          • #6
            Happy “settling” but only for a very short while!
            GBA Black; HTO Twilight/Tension interior; Z51 & Mag Ride; E60 lift; 5VM visible carbon fiber package; 5ZZ high wing; FA5 interior vis CF; ZZ3 engine appearance; 3LT; Q8T Spectra Gray Tridents; J6N Edge Red Calipers; SNG Edge Red Hashmarks; VQK Splash Guards; RCC Edge Red engine cover; VJR illuminated sill plates. Lifetime, annual contributors, and 23 year members of National Corvette Museum. Home is the beautiful Pacific Northwest.

            Comment


            • #7
              Hoping for a fast recovery for your C8 🙏🏻
              Arctic White 2LT, G8G, HUL, F9, AH2, 5ZZ, E60, STI, SHW J6F, Q8Q, RCC, Z51, ZYC.

              Comment


              • #8
                Had similar issue at less than 1,000 miles. Dealer was instructed to run car at idle multiple times to operating temp, shut down, repeat after cool down. This sequence was done at least 8-10 times. Fluid nor filter was changed. Currently have over 8,400 miles with no further issues. Most of these problems seem to happen when accelerating which cause some “particle” to dislodge causing the DCT to act erratically. Will be interested to see what your diagnosis will be!! Good Luck. See you at the BASH?
                GD0 Accelerate Yellow Metallic; 3LT; HUE Natural Napa Leather; AE4 Competition Sport Seats; FA5 CF Interior Trim; Z51; FE4 Mag Ride Suspension; E60 Front Lift; Q8Q CF Open Spoke Wheels; J6F BR Brembo Calipers; RCC ER Intake Cover; DTH CF Racing Stripes; ZZ3 Engine App Package; VQK Splash Guards; ERI Battery Protection; R8C Museum Delivery

                Proud LTM NCM.

                Comment


                • #9
                  AN OBSERVATION: Curious, if, of those C8 owners who have changed their Transmission Fluid prior to the recommended first Motor Oil/Filter & Transmission Oil/Filter change, have had an engine light or other issues with either engine or transmission. Perhaps these DCT “problems” would decrease if not disappear, if we as owners, did a preemptive Motor Oil, Transmission Oil & Filter Change out prior to 1st recommended maintenance.

                  I wonder if, of those MECF members who had changed out their oils & filters (Engine/Tranny) prior to 1st recommended maintenance interval, any have experienced any engine/tranny issues afterwards? If no one has, then there’s a possible solution.
                  07/01/20 Deposit @ VanBortels on 2021 C8 Coupe; 08/01/20 Prelim Order Status 1100; 01/21/21 Final Order Status 2000; 01/27/21 Status 3000; 03/06/21 Status 3300 (TPW 03/22/21); 03/16/21 Status 3400; 03/22/21 Status 3800; 03/23/21 Status 4B00; 03/26/21 Status 4D00: Status 4200; 04/02/21; 04/06/21 Status 5000; 2LT Coupe; GMO; DSZ; Q8Q; HTA; AQ9; E60; FE2; NPP; ERI

                  ”You only live once, but, if you live right, once is enough “

                  Comment


                  • #10
                    Originally posted by whl3 View Post
                    Had similar issue at less than 1,000 miles. Dealer was instructed to run car at idle multiple times to operating temp, shut down, repeat after cool down. This sequence was done at least 8-10 times. Fluid nor filter was changed. Currently have over 8,400 miles with no further issues. Most of these problems seem to happen when accelerating which cause some “particle” to dislodge causing the DCT to act erratically. Will be interested to see what your diagnosis will be!! Good Luck. See you at the BASH?
                    And was the transmission simply left in Park during these on/off cycles?
                    My C8:
                    '20 Elkhart Lake Blue 2LT Coupe, Natural Interior, GT2 Two-Tone Seats, Performance Exhaust, Front Lift, Carbon Flash Wheels, Engine Appearance Package 2000 Status December 27, 2019; 3000 Status January 2, 2020; 3400 Status March 10, 2020;TPW March 16, 2020; Built June 4th, 2020 (COVID-19); Delivery July 1, 2020

                    Current Vettes:
                    '68 Lemans Blue 327/350 Convertible
                    '91 Turquoise Convertible with Hardtop
                    '14 Lime Rock Green 2LT Convertible, Black Top, Kalahari, 7-Speed, Performance Exhaust

                    Comment


                    • #11
                      My trans filter was changed at 1400 miles. The only odd instance was a refusal to shift out of 1st, but that was 600 miles later. Still concerned about that.

                      I had a golf bag like your transmission - only the odd-numbered clubs.
                      C8 Coupe, Zeus Bronze, 3LT, TU7, HUE, GUI, CF7, EFY, EYK, J6N, NPP, E60, STI, VQK

                      Comment


                      • #12
                        Sorry abt this Mobius. If anybody can get to the bottom of it you can. Hang in there and keep us posted.

                        Comment


                        • #13
                          Originally posted by Boomer View Post
                          Sorry abt this Mobius. If anybody can get to the bottom of it you can. Hang in there and keep us posted.
                          I appreciate the vote of confidence.

                          Originally posted by whl3 View Post
                          Had similar issue at less than 1,000 miles. Dealer was instructed to run car at idle multiple times to operating temp, shut down, repeat after cool down. This sequence was done at least 8-10 times. Fluid nor filter was changed. Currently have over 8,400 miles with no further issues. Most of these problems seem to happen when accelerating which cause some “particle” to dislodge causing the DCT to act erratically. Will be interested to see what your diagnosis will be!! Good Luck.
                          Since I'm working from home, I tried this process. I cycled the car 7 times yesterday (20 minutes run time with 2 hours of cool-down) and once this morning.

                          Some observations:
                          • The CEL went out on the 3rd cycle, came back on the 4th cycle, and then stayed out from 5-8.
                          • The car will idle for 10 minutes and then auto shut-down. To over-ride this, before the 10 minutes expires, put your foot on the brake and place the car into Drive or Reverse for a few seconds. This resets the 10 minute count down.
                          • My code-reader picked-up a number of transmission codes
                          • I received an email and text message from Chevrolet that my C8 reported not feeling well.
                          • Of the roughly half-dozen C8 owners who have encountered this and described it online, I am the only one I've seen who lost the even gears.

                          After the 8th cycle this morning, I took the car out for a test drive, and I was happy to see the car quickly shift into 2nd as I headed down my street.

                          I took the car for about a 20 mile drive, switching through all Drive modes and with some "aggressive" acceleration mixed in. Everything seems to be back to normal. The CEL never returned.

                          Now, in the research that I've done on this issue, some have seen complete recovery (like whl3), while others have had the problem recur, with a range of transmission procedures (valve cleanings, fluid flush, etc.) providing temporary relief, but ultimately still requiring a transmission replacement.

                          I feel comfortable driving to my preferred dealership, about 40 miles away.

                          I'll continue to provide updates after my dealer visit and their recommendation(s).
                          Last edited by Mobius; 04-08-2021, 10:31 AM.
                          My C8:
                          '20 Elkhart Lake Blue 2LT Coupe, Natural Interior, GT2 Two-Tone Seats, Performance Exhaust, Front Lift, Carbon Flash Wheels, Engine Appearance Package 2000 Status December 27, 2019; 3000 Status January 2, 2020; 3400 Status March 10, 2020;TPW March 16, 2020; Built June 4th, 2020 (COVID-19); Delivery July 1, 2020

                          Current Vettes:
                          '68 Lemans Blue 327/350 Convertible
                          '91 Turquoise Convertible with Hardtop
                          '14 Lime Rock Green 2LT Convertible, Black Top, Kalahari, 7-Speed, Performance Exhaust

                          Comment


                          • #14
                            Originally posted by Mobius View Post

                            And was the transmission simply left in Park during these on/off cycles?
                            Yes it DCT was placed in "P" for all cycles!!
                            GD0 Accelerate Yellow Metallic; 3LT; HUE Natural Napa Leather; AE4 Competition Sport Seats; FA5 CF Interior Trim; Z51; FE4 Mag Ride Suspension; E60 Front Lift; Q8Q CF Open Spoke Wheels; J6F BR Brembo Calipers; RCC ER Intake Cover; DTH CF Racing Stripes; ZZ3 Engine App Package; VQK Splash Guards; ERI Battery Protection; R8C Museum Delivery

                            Proud LTM NCM.

                            Comment


                            • #15
                              Mine did and still does. GM took the car back. They did not want to pull the engine and transmission a second time. I did notice while in track mode there is only 6 speeds available. Below are the issues with what was going on with my 2020. GM replaced it with a Z51 HTC. Look at number 4 and 5




                              George
                              2020 CHEVROLET CORVETTE 2D 2LT List of discrepancies.
                              VIN 1G1Y72D4XL510XXX
                              1. Loud lifter noise at high way speeds of 50-70 mph. dealer fixed. (Engine and transmission were remove and lifters replaced and both were reinstalled. Communication Number: PIP5606E, Date: 2019-09-24
                                Category: 060000 ENGINE AND ENGINE COOLING
                                Summary: This Preliminary information communicates A vehicle may have a tick noise from the engine cold, initial start in the morning. A lifter may not have sufficient amount of oil during cold start operation (not pumped up). As information comes
                              2. Max speed stuck at 85mph from delivery
                              3. Starter seems at time to have an extended cycle to start. (seems to hang up)
                              4. While driving in all modes except manual shift the transmission has issues. From 3rd gear to 4th and from 4th to 5th when this happens the RPM increase significantly toward red line until the transmission actually shifts then the car accelerates to where I apply the brakes. This also accrues also in down shifting. The way I make sure this does not happen is I use the paddle shift to advance to the next gear while accelerating or during deceleration thus the clunking noise. See next line.
                              5. While driving the transmission does at times won’t recognize the odd gears while driving 2,4,6,8 but no odd gears.
                              6. There is a distinct noise from the engine compartment while driving. The lifters were changed but this is much different. Sounds like the whole valve train is coming apart especially with the transmission shifting issues.
                              7. When car is warmed up in idle there is a distinct ticking noise coming from the right exhaust but not the left exhaust. (have video)
                              8. Not all the time but when started there is a distinct smoke coming from the exhaust, mostly from the right exhaust port opening.
                              9. Rear view backup camera goes blue in both digital and analog then tries to correct itself in both modes thus not allowing me to see what’s behind me moving the vehicle forward or aft. (have video)
                              10. Rear view mirror flashes a green square at the upper left corner. (have video)
                              11. Check engine light flash three time then stayed on steady, the engine made a loud back fire with rough idling.
                              12. Engine at times has rough idle when coming to a stop at traffic light or stop sign. (The engine pauses but does not stop.) Seems to miss fire.
                              13. Driver display screen went blank at night then came back on.
                              14. When using the Drive mode selector from My-mode, Touring, Weather, Sport and Track the appropriate screen will not display.
                              15. PDR will not replay recordings.
                              16. Heads up Display (HUD) makes a constant noise but not all the time. This will also happen with the car in park and engine and ignition in off. Color portion of RPM in windshield went out but works when it want to.
                              17. With remote start car moves forward one foot then the parking brake sets itself.
                              18. At idle the oil pressure reads zero with the warning light on. Have picture.
                              19. Drive as well as center display went blank while driving at night.

                              Comment

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