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

Cadillac

ATS

2016

2017

Automatic 8L45, 8L90 (M5T, M5N, M5U, M5X)

CTS Models

CT6

Escalade Models

2015

Chevrolet

Camaro

2016

2017

Corvette

2015

2019

Silverado

GMC

Sierra

2015

2017

Automatic 8L90 (M5U, M5X)

Yukon

Involved Region or Country

North America and N.A. Export Regions

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.

Cause

This condition is due to the initial clutch fill time of the 2-3-4-6-8 (C4) clutch.

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.  

Correction

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.

Version

3

Modified

Nov. 18, 2016 - Revised the Cause section.

April 6, 2017 - Added models and Revised the Condition, Cause and Correction sections.