2024 C8 Trans shifting - Normal?
Race Director
Joined: Aug 2016
Posts: 12,866
Likes: 10,274
From: Garden Valley CA
Performance Shift mode expires after a few moments. Using the paddles puts you in temporary manual mode which reverts to Drive mode after several seconds. One pull, one shift. If you want to immediately put it back in Drive mode just pull and hold the + paddle. It will automatically shift back to the best gear for normal driving and put the car back in Drive mode. Alternately, if you want to play, pull and hold the - paddle. This will put you in the lowest gear possible for the conditions and put you in temporary manual mode. If you don't upshift it will automatically upshift for you at redline in temporary manual mode. If you use the manual mode button on the console it stays in manual mode and will bounce off the rev limiter at redline if you don't upshift. Don't be doing any of this if you don't have at least 500 miles on the car.
Last edited by RKCRLR; Jan 24, 2024 at 07:08 PM.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 35,067
Likes: 12,429
From: NE South Carolina
Thanks for the reply and info. If I am in Drive mode and not Manual using the paddles and I give it the throttle and this happens are you saying just hit the +paddle to get to a higher gear even if I started out in D mode? Sorry for the stupid question but I just got the car and am learning as I go. Input from others is the best way to get info.
Thanks
RJ
Thanks
RJ
This is a list of DCT features I made some time ago: This summary of the DCT feathers includes statements from GM’s DCT Controls Manager, a C8 forum post by Tadge and comments about "boosted shift" made by a GM engineer Ed Piatek. . Pretty impressive options.
- The C8 DCT transmission has different automatic shift strategies for the various drive modes, which adapt in real time. The more aggressive, the more spirited you drive, the more aggressive the car's responds, -start to relax, the car starts to relax.
- The DCT uses latitudinal and longitudinal accelerometers, and looks at information like throttle position and steering angle to gauge how the car is being driven, and react accordingly. In Track mode set to automatic, the car will downshift aggressively when the driver is braking hard into a corner, and hold upshifts until corner exit.
- The C8 has two manual modes. If you pull a paddle while in Drive, you get a temporary manual mode, which automatically times out, or can be exited sooner by holding the upshift paddle. In this mode, the car will automatically upshift at redline. If you press the M button in the center console, you get full manual mode. There's no time out, and the car won't upshift at redline.
- Hold the downshift paddle, the DCT will serve up the lowest possible gear. Do that while braking, and the transmission will keep downshifting as engine speed allows.
- Pulling both paddles at the same time is equivalent to pushing in the clutch pedal on a manual car, which allows you to rev the C8's new V-8 as much as you want.
- The paddles are directly wired to the transmission control module (TCM) for quicker response times. This doesn't mean the paddles will give you a downshift that over-revs the engine—the TCM prevents that.
- With the C8's Performance Launch mode, the car uses the inertia of the engine coming down between revs to propel the car forward. Frankl, GM has not provided many details on this feature. This is more info by GM’s Engineer Ed Piatek: “We found that during very aggressive launches we can drive torque through both shafts/clutches simultaneously which improves the 0 to 60 times.” Road and Track interpretation of that statement was: "With the C8's Performance Launch mode, the car will actually use the inertia of the engine coming down between revs to propel the car forward. Chevy calls these "Boosted Shifts," and they're only used with a Performance Launch."
- You can avoid V4 mode using the “M” manual button or temporally for 5 seconds after pulling the last shift paddle. The new "Z" mode comes from the factory set up as an extra sporty mode including shift schedules pulled from the "Track" mode, so that will be V8 only. You can customize "Z" mode any way you want, so if you elect another shift pattern, V4 mode will return.
Last edited by JerryU; Jan 25, 2024 at 01:25 PM.
Racer
Joined: Aug 2000
Posts: 317
Likes: 42
From: Chicago, Illinois
JerryU and everyone else, thanks for the great information! It all makes sense now and as I said, I just got the car about a month ago and have not had much seat time as I live in the Chicago suburbs. I am sure I'll catch on quick and will really enjoy the car. As always, the folks on the Forum are the best and are really good at sharing knowledge with everyone else.
RJ
RJ
Race Director
Joined: Nov 2003
Posts: 16,069
Likes: 4,152
From: Bergen county NJ
Your transmission selection is “track “ mode. That’s why you are experiencing this driving situation.
in my mode or z mode reset the transmission selection to sport and that driving experience will disappear.
some put track “ mode selection for the transmission in sport in z mode and “track” mode for my mode.
the track setting is what is causing the hang up.
in my mode or z mode reset the transmission selection to sport and that driving experience will disappear.
some put track “ mode selection for the transmission in sport in z mode and “track” mode for my mode.
the track setting is what is causing the hang up.
Race Director
Joined: Aug 2016
Posts: 12,866
Likes: 10,274
From: Garden Valley CA
Your transmission selection is “track “ mode. That’s why you are experiencing this driving situation.
in my mode or z mode reset the transmission selection to sport and that driving experience will disappear.
some put track “ mode selection for the transmission in sport in z mode and “track” mode for my mode.
the track setting is what is causing the hang up.
in my mode or z mode reset the transmission selection to sport and that driving experience will disappear.
some put track “ mode selection for the transmission in sport in z mode and “track” mode for my mode.
the track setting is what is causing the hang up.
Race Director
Joined: Nov 2003
Posts: 16,069
Likes: 4,152
From: Bergen county NJ
I found if I do not have the transmission or drivetrain I can’t remember which chosen in either my mode or z mode the transmission does not hang up after letting up on the accelerator pedal as described by the original poster.
track mode itself will hold the gear longer as well and I found it annoying on the street in normal driving.
just passing the information along.
good luck
track mode itself will hold the gear longer as well and I found it annoying on the street in normal driving.
just passing the information along.
good luck
