Bulletin No.: 23-NA-048

Service Bulletin

Date: August, 2024

TECHNICAL
Subject:

Brand:

Oil Leak from Center of Vehicle

Model:

Silverado 1500 LTD (RPO J21, VIN
Digit 5 = W/Y)
Chevrolet

Silverado 1500 New (RPO J22, VIN
Digit 5 = A/D)
Silverado 1500
Sierra 1500 Limited (RPO J21,
VIN Digit 5 = 8/9)

GMC

Sierra 1500 - New
(RPO J22, VIN Digit
5 = H/U)
Sierra 1500

Model Year:
from

to

2022

2022

2023

2023

2022

2022

2023

2023

VIN:
from

Engine:

Transmission:

to

L3B

Involved Region or Country

North America

Condition

Some customers may comment that an oil leak can be seen coming from the center of
vehicle
Some technicians may find oil leaking from the bell-housing area.

Cause

This condition may be caused by oil leaking past the rear crankshaft oil seal.

Correction

If the oil leak has been verified to be coming from the rear crankshaft seal, replace the
rear crankshaft oil seal and housing.

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.

Copyright 2024 General Motors. All Rights Reserved.

Page 2

August, 2024

Bulletin No.: 23-NA-048

Service Procedure

6538223

Important: To reduce rolling of the crankshaft seal. It is recommended to utilize the J-8608 and J-8092, to fully seat
the seal onto the crankshaft before tightening the bolts to the housing. Only using hand pressure, press the seal
protector/installer on the end of the crankshaft.
Refer to Crankshaft Rear Oil Seal and Housing Replacement.

Parts Information
Note: Only use the parts the coincides with the repair performed.
Causal
Part

Description

Part
Number

Qty

X

HOUSING,
CR/SHF RR OIL
SEAL

12737074

1

N/A

BOLT, A/TRNS
FLEX PLT

11548684

8

N/A

GASKET, EXH
SYS FRT

84407373

1

N/A

BOLT, RR S/ABS
LWR BRKT

11561300

1

N/A

GASKET, O/PMP
SUC PIPE

55487654

1

N/A

GASKET, TRFER
CASE ADAP

24245110

1

Bulletin No.: 23-NA-048
Causal
Part

Description

N/A

August, 2024
Part
Number

Qty

BOOT, TRFER
CASE FRT
OUTPUT SHF

84124171

1

N/A

SEAL, TRNS
CLR PIPE

85628205

1

N/A

OIL, ENGINE

N/A

SEALANT, RTV

Refer to EPC

Page 3

As Required
1

Warranty Information
For vehicles repaired under warranty, use:
Labor Operation

Description

Labor Time

4066250

Crankshaft Rear Oil Seal Housing Replacement

Use the Published Labor
Operations Time

Version

5

Modified

Released March 30, 2023
Revised May 04, 2023 - Update Labor Operation Number.
Revised June 07, 2023 - Update Trans Case Adapter Gasket Part Number.
Revised February 22, 2024 - Update Service Procedure section.
Revised August 22, 2024 - Updated HOUSING, CR/SHF RR OIL SEAL Part Number in
Parts 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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