16-NA-361

Bulletin No.:
Service Bulletin
Date:
16-NA-361
December, 2023
INFORMATION
Subject:
Brand:
Information on Transmission Harsh 1-2 Shift Upon First Start Up/Shift of the Day Under
Light Throttle
Model:
to
2016
2019
CT6
2016
2020
CT4
2020
2024
Escalade Models
2015
2017
Camaro
2016
2024
Colorado (VIN S, T)
2017
2024
Corvette
2015
2019
Express
2017
2024
Silverado
2015
2018
Silverado LD
2019
2019
Silverado 1500 (New
Model)
2019
2021
2022
2022
2023
2024
2017
2024
Sierra
2015
2018
Sierra Limited
2019
2019
Sierra 1500 (New
Model)
2019
2021
2022
2022
Sierra 1500
2023
2024
Yukon Models
2015
2017
ATS
CTS Models
Cadillac
Chevrolet
Silverado 1500 LTD
(RPO J21, 12th VIN
Digit = 4 or less)
Silverado 1500 New
(RPO J22, 12th VIN
Digit = 5 or greater)
Silverado 1500
Canyon
Savana
GMC
Model Year:
from
Sierra 1500 Limited
(RPO J21, 12th VIN
Digit = 4 or less)
Sierra 1500 New
(RPO J22, 12th VIN
Digit = 5 or greater)
Copyright 2023 General Motors LLC. All Rights Reserved.
VIN:
from
to
Engine:
Transmission:
(Automatic)
8L45 (M5N); 8L90
(M5X, MQE)
8L90 (M5U, MQE)
8L45, 8L80 (M5T,
MFC); 8L90 (M5U,
M5X, MQE)
—
—
—
8L45, 8L80 (M5T,
MFC); 8L90 (M5U,
M5X, MQE)
8L90 (M5U, MQE)
Page 2
December, 2023
Bulletin No.: 16-NA-361
Involved Region or Country
North America, Argentina, Brazil, Chile, Colombia, Ecuador, Peru, Europe, Middle East,
Israel, Japan, Cadillac Korea (South Korea), GM Korea Company, China, Thailand,
Philippines
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
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.
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.
Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following Labor Operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor
Operation
8481038*
Description
Labor Time
Confirmation Verification of
First 1-2 Shift of the Day
0.3 hr
*This is a unique Labor Operation for bulletin use only.
Version
10
Modified
Revised November 18, 2016 – Revised the Cause section.
Revised April 06, 2017 – Added models and revised the Condition, Cause and Correction
sections.
Revised July 20, 2017 – Updated Model section.
Revised May 21, 2018 – Updated Model section.
Revised October 08, 2019 – Added 2020 CT4 and updated models to 2020.
Revised August 10, 2020 – Added 2021 to Model Year and added Warranty Information
section.
Revised January 26, 2022 – Added the 2022 Model Year and updated the Involved
Region or Country section.
Revised October 19, 2023 – Added the 2023-2024 Model Years to certain models and the
Important statement above Warranty Information.
Revised December 20, 2023 – Added 8L80 (MFC) to Transmission section.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.
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