23-NA-156

Bulletin No.:
Service Bulletin
Date:
23-NA-156
November, 2023
INFORMATION
Subject:
Information on M1L Automatic Transmission Production Running Changes
Brand:
Model:
Chevrolet
Corvette
Model Year:
VIN:
from
to
from
to
2020
2024
P5137263
——
Involved Region or Country
Engine:
Transmission:
—
8-Speed
Automatic
(RPO M1L)
North America, Europe, Middle East, Japan, Australia/New Zealand
There is a production running change to the M1L transmission case design toward the
end of the 2023 model year.
The additional 1.89 L (2 quarts) of transmission fluid is no longer needed nor
recommended for track use for Z51 equipped Stingrays starting with this VIN. In the
future, be aware that service transmissions will also begin to migrate to this updated
design for older model years and will require additional parts to be ordered when used in
an older model year.
Note: The canister filter for regular maintenance remains unchanged.
Information
6420769
To identify a new Die3 transmission easily, the new Die3 only has 4 fasteners along the
front edge of the sump pan, where the old Die2 transmission has 6 fasteners along the
front edge of the sump pan. Refer to the graphic above.
Copyright 2023 General Motors LLC. All Rights Reserved.
Page 2
November, 2023
Bulletin No.: 23-NA-156
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
3
Modified
Released September 06, 2023
Revised September 08, 2023 – Removed TUN Note from the Information section.
Revised November 15, 2023 – Added the 2024 Model Year.
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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