[indyz]

Thanks Need4Camaro, good info

[Chutzpah]

Yep, no issues with these trannies...smooth as silk.

2015 - 2017 Corvette: GM TechLink: Diagnostic Tips for Harsh
Shifting Transmission Conditions
Diagnostic Tips for Harsh Shifting Transmission Conditions

June 10, 2017
Harsh shifting conditions and delayed garage shift engagements may be noticed on some 2017 Colorado, Canyon, Express, Savana; 2016-2017 ATS, CT6, CTS, Camaro; 2015 - 2017 Escalade, Silverado, Sierra, Yukon Denali, and Corvette models equipped with the 8L45 or 8L90 automatic transmission (RPOs M5N, M5T, M5U, M5X). The harsh shift conditions may be caused by one or more clutch fill times not completely learned in the Transmission Control Module (TCM).

DTCs and Updated Calibrations
As a starting point for diagnosing all 8L45/8L90 transmission shift conditions, check for DTCs in all modules and address the causes for setting the DTCs. Also check for any available ECM/TCM calibration updates.

Refer to the following bulletins for additional information:
16-NA-411 – 2015-2016 models equipped with the 6.2L engine (RPO L86) engine and the 8L90 transmission

9/13/2017 2015 - 2017 Corvette: GM TechLink: Diagnostic Tips for Harsh Shifting Transmission Conditions - Print View
http://www.corvetteactioncenter.com/...rint-1380.html

16-NA-412 – 2015-2016 models equipped with the 5.3L engine (RPO L83) engine and the 8L90 transmission
16-NA-404 – 2017 models

Test Drive with GDS2
A test drive of the vehicle should be completed in order to attempt to duplicate the concern. Use GDS2 to capture a session log of the event and bookmark when the shift concern is identified. Review the GDS2 session log to identify which shift(s) are occurring at each bookmark.

Refer to the following bulletins for additional information:
14-07-30-001: Information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares – 2015 Corvette
16-NA-411, 16-NA-412 and 16-NA-019: Updating ECM/TCM Calibrations – 2015 models other than Corvette
16-NA-019: Information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares – 2016-2017 models

These bulletins are based on the following criteria:
2015 models with 7,500 miles (12,000 km) or less since the vehicle in-service date, TCM calibration update or the Service Fast Learn (SFL) procedure being performed
2016 models with 5,000 miles (8,000 km) or less since the vehicle in-service date, TCM calibration update or the SFL procedure being performed
2017 models with 2,500 miles (4,000 km) or less since the vehicle in-service date, TCM calibration update or the SFL procedure being performed

Transmission, valve body or TCM replacement requires a Service Fast Learn procedure using a scan tool to be performed in order for the TCM to learn individual clutch apply pressures. If the TCM calibration has been updated, a Service Fast Learn procedure is required on vehicles with any mileage accumulation.

Clutch Drive Learn Procedure
Based on the bookmarks placed in the GDS2 session, complete the Clutch Drive Learn procedure for the suspect clutch. The Clutch Drive Learn procedure should only be performed on smooth, level roads and may take 45 minutes or more.

Completion of the Service Fast Learn procedure will reset all shift adapts and may require the entire transmission Clutch Drive Learn procedure for each clutch to be completed.
After completing the procedure, the vehicle should be allowed to cool down for eight or more hours and then test driven again to ensure the cold shift quality is acceptable.

Refer to the following bulletins for more information:
16-NA-361: Transmission Harsh 1-2 Shift Upon First Start Up/Shift of the Day Under Light Throttle
16-NA-213: Diagnostic Tips for Harsh Shifts after Mileage Accumulation without Previous Transmission

Repairs and/or Calibration Updates – Transmissions built between July 1, 2015 and September 14, 2015.

Garage Shifts
Refer to the following bulletins for more information:
16-NA-014: Delayed Engagement After Sitting With Engine Off. Torque Converter Fluid Drain Back – 2015-2016 models

16-NA-364: Delayed Engagement After Sitting With Engine Off, Clutch Slow to Fill – 2015-2017 models

[Need4Camaro]

well, she aint perfect but...I still love my A8. Admittedly when I go back to drive my LS1 Z28 it feels like its missing 4 gears haha.

[DiGiam]

Originally Posted by Chutzpah

Yep, no issues with these trannies...smooth as silk.

2015 - 2017 Corvette: GM TechLink: Diagnostic Tips for Harsh
Shifting Transmission Conditions
Diagnostic Tips for Harsh Shifting Transmission Conditions

June 10, 2017
Harsh shifting conditions and delayed garage shift engagements may be noticed on some 2017 Colorado, Canyon, Express, Savana; 2016-2017 ATS, CT6, CTS, Camaro; 2015 - 2017 Escalade, Silverado, Sierra, Yukon Denali, and Corvette models equipped with the 8L45 or 8L90 automatic transmission (RPOs M5N, M5T, M5U, M5X). The harsh shift conditions may be caused by one or more clutch fill times not completely learned in the Transmission Control Module (TCM).

DTCs and Updated Calibrations
As a starting point for diagnosing all 8L45/8L90 transmission shift conditions, check for DTCs in all modules and address the causes for setting the DTCs. Also check for any available ECM/TCM calibration updates.

Refer to the following bulletins for additional information:
16-NA-411 – 2015-2016 models equipped with the 6.2L engine (RPO L86) engine and the 8L90 transmission

9/13/2017 2015 - 2017 Corvette: GM TechLink: Diagnostic Tips for Harsh Shifting Transmission Conditions - Print View
http://www.corvetteactioncenter.com/...rint-1380.html

16-NA-412 – 2015-2016 models equipped with the 5.3L engine (RPO L83) engine and the 8L90 transmission
16-NA-404 – 2017 models

Test Drive with GDS2
A test drive of the vehicle should be completed in order to attempt to duplicate the concern. Use GDS2 to capture a session log of the event and bookmark when the shift concern is identified. Review the GDS2 session log to identify which shift(s) are occurring at each bookmark.

Refer to the following bulletins for additional information:
14-07-30-001: Information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares – 2015 Corvette
16-NA-411, 16-NA-412 and 16-NA-019: Updating ECM/TCM Calibrations – 2015 models other than Corvette
16-NA-019: Information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares – 2016-2017 models

These bulletins are based on the following criteria:
2015 models with 7,500 miles (12,000 km) or less since the vehicle in-service date, TCM calibration update or the Service Fast Learn (SFL) procedure being performed
2016 models with 5,000 miles (8,000 km) or less since the vehicle in-service date, TCM calibration update or the SFL procedure being performed
2017 models with 2,500 miles (4,000 km) or less since the vehicle in-service date, TCM calibration update or the SFL procedure being performed

Transmission, valve body or TCM replacement requires a Service Fast Learn procedure using a scan tool to be performed in order for the TCM to learn individual clutch apply pressures. If the TCM calibration has been updated, a Service Fast Learn procedure is required on vehicles with any mileage accumulation.

Clutch Drive Learn Procedure
Based on the bookmarks placed in the GDS2 session, complete the Clutch Drive Learn procedure for the suspect clutch. The Clutch Drive Learn procedure should only be performed on smooth, level roads and may take 45 minutes or more.

Completion of the Service Fast Learn procedure will reset all shift adapts and may require the entire transmission Clutch Drive Learn procedure for each clutch to be completed.
After completing the procedure, the vehicle should be allowed to cool down for eight or more hours and then test driven again to ensure the cold shift quality is acceptable.

Refer to the following bulletins for more information:
16-NA-361: Transmission Harsh 1-2 Shift Upon First Start Up/Shift of the Day Under Light Throttle
16-NA-213: Diagnostic Tips for Harsh Shifts after Mileage Accumulation without Previous Transmission

Repairs and/or Calibration Updates – Transmissions built between July 1, 2015 and September 14, 2015.

Garage Shifts
Refer to the following bulletins for more information:
16-NA-014: Delayed Engagement After Sitting With Engine Off. Torque Converter Fluid Drain Back – 2015-2016 models

16-NA-364: Delayed Engagement After Sitting With Engine Off, Clutch Slow to Fill – 2015-2017 models

A really technical way to say,"Our transmission is shit"..lol

[cwoodard91]

So I have already witnessed the "shuddering problem while cruising" from the transmission so I took to the car to the dealer and they replaced the transmission fluid which seemed to fixed the shuddering issue. But now I have a problem where, if I have the car in sport or track mode and I'm cruising around 60mph then floor it, the car will downshift fast as normal but when it upshifts it will shift really hard then pause for a second or 2 and the traction control light will flash. Now I know the car is not spinning the tires because I'm going about 60mph on a bone dry freeway and I can easily replicate this issues. Wondering if its the trans or the diff slipping.

Any ideas?

[GroundhogSS]

Originally Posted by cwoodard91

So I have already witnessed the "shuddering problem while cruising" from the transmission so I took to the car to the dealer and they replaced the transmission fluid which seemed to fixed the shuddering issue. But now I have a problem where, if I have the car in sport or track mode and I'm cruising around 60mph then floor it, the car will downshift fast as normal but when it upshifts it will shift really hard then pause for a second or 2 and the traction control light will flash. Now I know the car is not spinning the tires because I'm going about 60mph on a bone dry freeway and I can easily replicate this issues. Wondering if its the trans or the diff slipping.

Any ideas?

You may be getting the torque converter problem some guys have had. Many have had the converter replaced at the dealer.

[whiskeyfed]

Originally Posted by Need4Camaro

FOR ALL THOSE EXPERIENCING THIS ISSUE:

HERE IS THE FIX:



While its not exactly a PROBLEM persee, GM is aware of this issue and there IS a fix for it... There is actually TSP issue related to the TCM. I was experiencing this and took it in and they re-calibrated my TCM and the issue went away. It hasn't been doing it since... Here...read my thread and at the very end you will see the solution:

http://www.camaro6.com/forums/showthread.php?t=518185

Need4Camaro, thanks for the post! However, I had this done a while ago and it may have been somewhat of a placebo effect on me but my car is still doing this. Although i can attribute the harsh 1-2 on the TCM being cold because it doesn't happen after that. I do get extremely sharp shifts (not the good sharp) from like 4-5 under WOT. I had to bring mine to the dealership 4 times and the first 3 times, they "could not replicate." On my way back from CamaroFest, my TM was SLIPPING gears! I was in traffic both in auto and manual mode, revving 3rd gear to around 3-4k and without shifting, the TM would clunk back down to about 2k and continue in the same gear... I am planning on tuning so I want to get this solved before that.

[craigss50]

Mine goes in Tuesday for transmission fluid flush. Servisor told me it corrects the issue 90% of the time. If still having issues they will replace torque converter. Sound like you have one of the 10% that needs TC replacement. Mine did not start acting up until I reached 4000 miles.

[whiskeyfed]

Originally Posted by craigss50

Mine goes in Tuesday for transmission fluid flush. Servisor told me it corrects the issue 90% of the time. If still having issues they will replace torque converter. Sound like you have one of the 10% that needs TC replacement. Mine did not start acting up until I reached 4000 miles.

Thanks Craig. Keep us updated

[z2f2ss]

mine goes in wednesday for tranny fluid replacement....im sick of this car by now. those that have had to replace it 3 times or more why didnt you just lemon the car?

[craigss50]

Originally Posted by whiskeyfed

Thanks Craig. Keep us updated

I just got back from the dealership and the transmission flush worked for my car. What a difference from when I took it in and how it shifts now.

[aldaran]

I felt the same rough shift and thought it was normal back then, then the shuddering started. Took the car in and the dealer replaced the torque converter. The car ran smooth for a while, but the rough shifting is coming back and I bet the shuddering will start again as well. My warranty runs out in December so hopefully it happens before then.

[cwoodard91]

Here is a video I made of my transmission seeming to slip during gear shifts. The car will Shift really hard followed by the traction control light flashing. Does this in any mode.

https://youtu.be/PH103Nx-xM4

[whiskeyfed]

So today on my way to work I figured out how to replicate my issue with consistency. When i am going at "in traffic" speed. So like stop and go, traffic. Light throttle input from a stop (like maybe 10% throttle) the car will literally jerk forward out of first gear into 2nd. I did this 4 times on my drive in by stopping and inching forward. This happened in drive (any mode) and also in manual mode shifting myself. The car was sufficiently warmed up. 2nd to 3rd it gets better but isn't great, and 3rd-8th seems fine.

The only way I can describe it in text is this:
Come to a complete stop,
inch forward in 1st gear,
when the TM wants to shift to 2nd, the car will jump about 200 RPM, hang there for a half a second or so, (in AUTO)
jerk into 2nd gear. It actually spilled my coffee

I do not seem to have any issues with any other gear but i very very rarely drive in Automatic because of these issues so I couldn't really say with any confidence that this doesn't happen in 2-8. I have been learning to drive around the issue by letting 1st rev out a little longer in manual mode (to about 3-3500 RPM) and then shifting myself. It is very annoying but it is getting me by.