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A8 Shift Issues

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Old Jun 3, 2018 | 08:27 AM
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Default A8 Shift Issues

Noticed that my car has issues with the following:

1) Downshifts from 3-1 when slowing down. Car seems to “jump” a bit.
2) Upshifting between 4th and 5th when giving medium throttle levels. Seems to “slip” a bit.

My car has about 5100 miles. 2017 Grand Sport w A8. Anyone have any thoughts? It will probably have to go to the dealer soon.

Thanks.
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Old Jun 3, 2018 | 08:58 AM
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Shifting from 3-1 is normal upon slowdown.
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Old Jun 3, 2018 | 09:01 AM
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Thanks figured it was. However it is not a smooth shift very often.
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Old Jun 3, 2018 | 10:35 AM
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They had problems with the TQ on the 15’s.Maybe also some 16’s.I have never ever felt A perfect automatic.
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Old Jun 3, 2018 | 10:38 AM
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My 2016 Z06 (March 2016 production) has always had a smooth 3 to 1 downshift. The 4 to 5 shift anomaly you are feeling is probably due to a brief torque converter clutch lock in 4th before it unlocks for the shift to 5th and then locks again. Converter clutch lockup is fairly abrupt in most transmissions now as part of the fuel economy strategy and it is fairly noticeable with most transmissions to the point of appearing like a separate shift event. When unlocked the normal "slippage" of an open converter will be noticeable.

The dealership may be able to help with a relearn for the abrupt downshift and it will also be a good chance for them to check that the transmission has any updated calibrations that may have been released since it was produced.
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Old Jun 3, 2018 | 10:39 AM
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Originally Posted by andy21
Noticed that my car has issues with the following:

1) Downshifts from 3-1 when slowing down. Car seems to “jump” a bit.
2) Upshifting between 4th and 5th when giving medium throttle levels. Seems to “slip” a bit.

My car has about 5100 miles. 2017 Grand Sport w A8. Anyone have any thoughts? It will probably have to go to the dealer soon.

Thanks.
My 2017 does the same thing. The “slip” in mine occurs during moderate acceleration at around 2500 RPM when shifting from 4 to 5. Another member here explained that the dip in RPM occurs during torque converter lock-up.
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Old Jun 3, 2018 | 11:02 AM
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my 2017 GS shifts smoothly except for the first couple of cold shifts out of the garage. Its mostly first to second where I get a hard jolt once warm its perfect. Its a strange transmission.
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Old Jun 3, 2018 | 11:04 AM
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I had the same issue on my 2017 A8 GS.. I did a couple of the fast learning procedures especially for the 3-1 downshift.. It seems to have reduced the harshness on the 3-1 downshift.. Here is a link to the GM Document for the procedure..

https://www.revbase.com/BBBMotor/TSb...dPdf?id=192824
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Old Jun 3, 2018 | 11:20 AM
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Originally Posted by C5Driver
my 2017 GS shifts smoothly except for the first couple of cold shifts out of the garage. Its mostly first to second where I get a hard jolt once warm its perfect. Its a strange transmission.
After the initial start of the day with your foot on the brake put it in manual mode and paddle shift to 2nd for a second and then back to 1st. This pre-fills the C4 clutch pack actuator and avoids the slow C4 actuator fill that creates the initial rough 1 to 2 shift. You can then either put it back in drive or continue in manual mode.

Driven this way my 2016 does not have the harsh initial 1 to 2 upshift.
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Old Jun 3, 2018 | 03:08 PM
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Originally Posted by andy21
Noticed that my car has issues with the following:

1) Downshifts from 3-1 when slowing down. Car seems to “jump” a bit.
2) Upshifting between 4th and 5th when giving medium throttle levels. Seems to “slip” a bit.

My car has about 5100 miles. 2017 Grand Sport w A8. Anyone have any thoughts? It will probably have to go to the dealer soon.

Thanks.
(1) Yep, that's normal.
(2) What you may be feeling is the torque converter locking during the change. Mine will do that at times during slight to normal acceleration.
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Old Jun 3, 2018 | 09:36 PM
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Originally Posted by NSC5
After the initial start of the day with your foot on the brake put it in manual mode and paddle shift to 2nd for a second and then back to 1st. This pre-fills the C4 clutch pack actuator and avoids the slow C4 actuator fill that creates the initial rough 1 to 2 shift. You can then either put it back in drive or continue in manual mode.

Driven this way my 2016 does not have the harsh initial 1 to 2 upshift.
I do this too, and no problems from a first harsh shift.
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