21NA238

Bulletin No.:
Service Bulletin
Date:
21-NA-238
November, 2021
TECHNICAL
Subject:
Transmission Fluid Leak Near Bellhousing Area
Model Year:
Brand:
Model:
Chevrolet
Silverado
2500HD/3500HD
GMC
Sierra
2500HD/3500HD
from
to
2020
2021
VIN:
from
to
Engine:
Transmission:
L5P
MGM, MGU
Involved Region or Country
North America
Condition
Some customers may comment that a transmission fluid leak is coming from the
bellhousing inspection cover.
Cause
This condition may be caused by the Automatic Transmission Case Front Cover Seal
may be rolled or damaged
Correction
If the leak has been verified to be coming from the front cover seal, replace the Automatic
Transmission Case Front Cover Seal and the Torque Converter Fluid Seal.
Service Procedure
Refer to Automatic Transmission Case Front Cover
Removal/Install and Torque Converter Fluid Seal
Removal/Installation in SI.
Parts Information
Causal
Part
Description
Part
Number
Qty
X
SEAL, T/C FLUID
24293986
1
X
SEAL AUTO
TRANS FRT
CASE COVER
24277112
1
N/A
BOLT, TRNS MNT
11548787
2
N/A
NUT, TRNS MNT
11548414
3
N/A
SEAL, OUTPUT
SEAL
SQUARE CUT
24286193
1
N/A
FLUID, AUTO
TRNS ULV
19352619
(U.S.)
19352620
(Canada)
8
Copyright 2021 General Motors LLC. All Rights Reserved.
Page 2
November, 2021
Bulletin No.: 21-NA-238
Labor Operation
Description
Labor Time
8466580
Automatic Transmission Case Front Cover Seal Replacement
Use the Published Labor
Operations Time
Warranty Information
For vehicles repaired under warranty, use:
Version
1
Modified
Released November 09, 2021
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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