| Subject: | Information on Transmission Harsh 1-2 Shift Upon First Start Up/Shift of the Day Under Light Throttle |
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Brand: |
Model: |
Model Year: |
VIN: |
Engine: |
Transmission: | ||
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from |
to |
from |
to | ||||
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Cadillac |
ATS |
2016 |
2017 |
Automatic 8L45, 8L90 (M5T, M5N, M5U, M5X) |
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CTS Models |
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CT6 |
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Escalade Models |
2015 |
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Chevrolet |
Camaro |
2016 |
2017 |
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Corvette |
2015 |
2019 |
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Silverado |
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GMC |
Sierra |
2015 |
2017 |
Automatic 8L90 (M5U, M5X) |
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Yukon |
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Involved Region or Country |
North America and N.A. Export Regions |
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Condition |
Some customers may comment that the transmission exhibits a harsh 1-2 shift on the first shift of the day, typically under light throttle. |
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Cause |
This condition is due to the initial clutch fill time of the 2-3-4-6-8 (C4) clutch. |
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Information |
Some customers may experience a flare condition on the first 1-2 shift of the day or after the vehicle has been parked for several hours. The condition may have developed after the replacement of a complete transmission assembly or the replacement of the stator support to correct a delayed engagement condition. This is most likely to occur under light throttle conditions. Subsequent 1-2 shifts have acceptable shift feel. Replacing transmission components will not correct the condition. |
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Correction |
Important: Replacing transmission components or complete assemblies will not improve the condition. The first 1-2 shift of the day may be harsh. The customers’ vehicle should be compared to a like vehicle under the same driving conditions. Do Not replace any parts for this condition. Note: This condition will not impact the designed performance or reliability of the vehicle. |
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Version |
3 |
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Modified |
Nov. 18, 2016 - Revised the Cause section. April 6, 2017 - Added models and Revised the Condition, Cause and Correction sections. |
Article ID: 1354
Created: April 9, 2017
Last Updated: August 12, 2020
Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article/2015-2019-corvette-service-bulletin-16-na-361-information-on-transmission-harsh-1-2-shift-upon-first-start-up-shift-of-the-day-under-light-throttle-1354.html