22-NA-182

Bulletin No.:
Service Bulletin
Date:
22-NA-182
March, 2024
INFORMATION
Subject:
Information on 6L80 6L90 8L90 10L80 10L90 10L1000 Equipped Vehicles With A Harsh
Shift, Shudder, Surge, Stall, Neutral/Flare, Transmission Overheating and/or High
Transmission Fluid Temperature
This bulletin replaces PIP5792E. Please discard PIP5792E.
Engine:
Transmission:
2024
L87,
LM2, LT4
MHS MHO MQC
2021
L84,
L8Z, LM2
MHS, MHT, MQB
MQC MQE MYC
2022
L84,
L8Z, LM2
MHS MHT MQB
MQC MQE MYC
2023
L84 L87
LM2, LZ0
MHS, MHT, MQB,
MQC MQE MYC
Silverado 2500HD
3500HD
2021
L5P, L8T
MKM, MGM,
MGU, MYD
Suburban
2021
L84,
L87, LM2
MHS MQC
Tahoe
2021
L84,
L87, LM2
MHS MQC
Sierra 1500
2021
2021
L84,
L8Z, LM2
MHS MHT MQB
MQC MQE MYC
Sierra 1500 Limited
(RPO J21, VIN Digit
5 = 8 / 9)
2022
Sierra 1500 New
(RPO J22, VIN Digit
5 = H / U)
2022
L84,
L87, LM2
MHS MHT MQB
MQC MQE MYC
2022
Sierra 1500
2022
L84, L87,
LM2, LZ0
MHS, MHT, MQB,
MQC, MQE, MYC
Sierra 2500HD
3500HD
2021
L5P, L8T
MKM, MGM
MGU MYD
Yukon
2021
L84,
L87, LM2
MHS MQC
Brand:
Model:
Cadillac
Model Year:
from
to
Escalade
2021
Silverado 1500
2021
Silverado 1500 LTD
(RPO J21, VIN Digit
5 = W / Y)
2022
Silverado 1500 New
(RPO J22, VIN Digit
5 = A / D)
2022
Silverado 1500
Chevrolet
GMC
Copyright 2024 General Motors LLC. All Rights Reserved.
2024
2024
VIN:
from
to
Page 2
March, 2024
Bulletin No.: 22-NA-182
Involved Region or Country
North America, Uzbekistan, Middle East, Brazil (Mercosur), Colombia (West), Ecuador
(West), Peru (West), Japan, Cadillac Korea (South Korea), Thailand (ASEAN), Europe,
Australia, New Zealand.
Condition
Some customers may comment on one or more of the following before or after the
transmission has been overhauled:
• Harsh shifting
• Shudder
• Surging
• Stalling
• Neutral/Flare
• Transmission overheating
Some customers may also comment on above normal transmission fluid temperature.
Cause
This condition may be caused by a twisted cooler line on low mileage vehicles.
Note: A twisted cooler line may cause DTC P27EC to set in the TCM on ETRS
transmissions. (RPO MHS MQC).
Information
5758376
Inspect for a twisted cooler line, example shown in the graphic above.
In some cases, it may be necessary to remove the under-body panels in order to clearly
see the cooler lines.
• If the cooler line is twisted, disconnect the cooler line from the transmission auxiliary
cooler and untwist it, then reconnect the cooler line.
• If the cooler line remains misshaped after untwisting, the cooler line should be
replaced then check the transmission fluid level following SI. Add fluid if needed.
• If no concerns are found with the rubber line being misshaped, check the transmission
fluid level following SI. Add fluid if needed.
The Thermal Bypass Valve (TBV) may be the cause of the overheat if a cooler line is not
twisted or misshaped. The TBV will open at the following temperatures for the models
listed in this TSB:
• 6 Speed (6L80, 6L90) - 158F (70C) - TBV is external to the transmission.
• 8 Speed (8L90) - 194F (90C) – TBV is external to the transmission.
• 10 Speed (10L80, 10L90, 10L1000) – 143F (61C) – TBV is within the valve body on all
listed applications except those equipped with 3.0 (LM2) (LZ0) Diesel. The (LM2) and
(LZ0) Diesel, the TBV is on the frame rail, external to the transmission and opens at
194F (90C).
Bulletin No.: 22-NA-182
March, 2024
Page 3
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.
Version
4
Modified
Released September 06, 2022
Revised December 19, 2022 - Added Neutral/Flare to Subject and Condition section.
Revised August 15, 2023 - Added 2024 Model Year and RPO MKM to Heavy Duty
Transmission section.
Revised February 26, 2024 - Add LZ0 to Engine section and Update the Last Paragraph
in the Information 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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