NHTSA ID Number: 10245773
Manufacturer Communication Number: 120421001B
TSB/Document Date: 2023-12-04
Summary
Transfer Case Identification First Design vs. Second Design
File in Section:
Bulletin No.:
Service Bulletin
Date:
04 - Driveline/Axle
12-04-21-001B
April, 2013
INFORMATION
Subject:
Transfer Case Identification First Design vs. Second Design
Models:
2007-2013 Cadillac
Escalade Models
2007-2013 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2007-2013 GMC Sierra, Yukon, Yukon Denali
Equipped with Magna X2T Transfer Case (RPOs NQF, NQG, NQH or NP0)
This bulletin is being revised to add the 2013 model year, clarify the information from the
previous bulletin and to add data throughout. The document should be reviewed and
treated as new information. Please discard Corporate Bulletin Number 12-04-21-001A
(Section 04 – Driveline/Axle).
The purpose of new product information is to document
important product changes that occur either model
year-to-model year or interim model year.
Changes may include one or more of the following
items:
• Specification changes
• New sealants and/or adhesives
Copyright 2013 General Motors LLC. All Rights Reserved.
•
•
•
•
•
Disassembly and assembly procedure revisions
Mechanical and diagnostic procedure revisions
New special tools required
Interim model year design changes
A component comparison from the previous
model year
Page 2
April, 2013
Bulletin No.: 12-04-21-001B
Interim Model Year Design Change – NQF/NQG/NQH/NPO Front Output Shaft,
Deflector, Seal
2512401
Interim 2012 model year, a new design front output
shaft deflector (3) was implemented into production for
second design NQF–HD/SHD and NQG–HD
applications. First design 2011 model year NQF and
NQG applications can be identified as not having the
deflector on the front output shaft.
For service, the new design front output shaft, deflector
and new design seal may be installed on current and
prior model year Magna NQF–HD/SHD, NQG–LD/HD,
NQH–LD/HD and NP0 applications providing the new
design front output shaft is also installed. The front
output shaft deflector is to be installed using the J 8092
driver handle (1) and DT 50649 seal installer (2).
Bulletin No.: 12-04-21-001B
April, 2013
Page 3
2512403
The new design deflector (1) can be installed onto all
current and prior model year Magna RPOs NQF, NQG,
NQH and NPO applications providing the new design
front output shaft (2) is also installed. Second design
front output shafts can be identified by the machined
area on the OD output end of the shaft (2). First design
front output shafts can be identified by the dust boot
clamp groove (3) located at the OD output end of the
shaft. The new design slinger will NOT install onto the
first design shafts.
Page 4
April, 2013
Bulletin No.: 12-04-21-001B
Service Parts Release Usage Change – NQH/NPO Control Actuator Levers
1817244
Light Duty (LD) 2007-2010 MP3023-NQH and 2010
MP3010-NP0 production transfer cases are built with
LD control actuator levers (3 and 6) and are used with
13 mm (0.52 in) diameter control actuator lever balls (5).
Heavy duty (HD) 2007-2010 MP3024-NQH production
transfer cases are built with HD control actuator levers
(3 and 6) and are used with Heavy 10 mm (0.39 in)
control actuator lever balls.
When replacement of one or both of the LD control
actuator levers is required, it is necessary to replace
both of the levers and all three balls with the HD
components as a set. It is also necessary to
re-measure and adjust clutch pack clearances as
required and to perform the Transfer Case High/Low
Clutch Reset. Refer to Measuring/Adjusting Clutch
Assembly Height in Transfer Case Assemble, Transfer
Case Description and Operation and Transfer Case
High/Low Clutch Reset. Heavy duty (HD) components
are the only parts available for service.
Bulletin No.: 12-04-21-001B
April, 2013
Page 5
Interim Model Year Design Change – NQG High/Low Shift Fork, Fork Pad, and High/
Low Clutch
2714413
Interim 2012 model year the High/Low shift fork, fork
pad and High/Low clutch design changed. The first
design forks (2) can be identified as having three flat
un-notched fork pad areas with three separate fork
pads (1). The second design forks (4) can be identified
as having a half-round shaped pad area with three
notches for pad orientation and installation and upper
and lower half-round fork pads (3). The second design
shift fork (4) and pads (3) are the only design available
for service and must be used with the second design
High/Low clutch.
Interim 2012 model year the High/Low shift fork, fork
pad and High/Low clutch design changed. The first
design high/low clutch (1) can be identified by having a
73 mm (2.87 in) OD rear flange (2). The second design
high/low clutch (3) can be identified by having a
76 mm (2.99 in) OD rear flange (4).
For service:
• The first design 73 mm (2.87 in) high/low clutch
may NOT be used with the second design fork
and pad.
• The second design 76 mm (2.99 in) high/low clutch
must be used with the second design fork and
fork pad.
2714414
Page 6
•
April, 2013
The second design 76 mm (2.99 in) high/low clutch
may also be used with the first design fork and
pad if first design fork replacement is not required.
Interim Model Year Design Change –
NQF/NQG/NQH Front Case Half
Assembly, Input Shaft, Planetary
Carrier High/Low Clutch
Interim 2012 model year for Magna light-duty and
heavy-duty transfer case RPOs NQF / NQG / NQH, a
second-design front case half assembly, planetary
internal gear, gear retaining ring, locking plate, thrust
washer-front, input shaft, pilot bearing, thrust
washer-rear, high/low planetary carrier and high/low
clutch were implemented into second-design
assemblies.
The second-design light duty (LD), heavy duty (HD),
and super-heavy duty (SHD) applications have a
reduced OD dimension carrier and the second-design
planetary internal gear has a reduced ID dimension.
The planetary internal gear is a press-fit
non-serviceable component and must be serviced with
the front case half assembly. In service it is possible
that a new or remanufactured transfer case may
contain first or second-design content.
If a second-design transfer case has been installed into
a vehicle that originally contained a first-design
assembly, TCCM reprogramming is not required.
Bulletin No.: 12-04-21-001B
For production, the following transfer cases variations
were produced:
• 2007-12i Magna LD NQG/NQH – produced with
first-design content. First design service
components are available. A second-design
assembly may be used for back-service in a
first-design application.
• 2007-10 Magna HD NQF – produced with only
first-design content. Service components are
available.
• 2007-10 Magna HD NQG – produced with only
first-design content. Service assemblies may
contain either first or second design content. Both
first and second design service components are
available.
• 2007-12i Magna HD NQH – produced with
first-design content. First design service
components are available. A second-design
assembly may be used for back-service in a
first-design application.
• 2011-12i Magna SHD NQF/NQG – produced with
first design content. First design service
components are available. A second-design
assembly may be used for back-service in a
first-design application.
• 2012i-13 Magna LD NQG/NQH – produced with
second-design content. Second design service
components are available.
• 2012i-13 Magna HD NQH – produced with
second-design content. Second design service
components are available.
• 2012i-13 Magna SHD NQF/NQG – produced with
second-design content. Second design service
components are available.
Bulletin No.: 12-04-21-001B
April, 2013
Page 7
Production Assembly Breakpoints
The design level and component content of the transfer
case can be determined by referencing the assembly
part number located on the identification label.
Production Assembly Breakpoints
Approximate
Production
Breakpoint
First Design
Assembly PN
Second Design
Assembly PN
24256476
24261560
NP0
March 2012
K100 / MYC
24256475
24261517
NQH
January 2012
K200 / MYD
24256474
24261516
NQH
January 2012
K100 / M99
24256473
24261515
NQH
January 2011
K100 / M30
24256472
24261514
NQH
December 2011
K100 / MYC
24257578
24261513
NQF
December 2011
K200 / MYD
24257577
24261512
NQF
January 2012
K200 / 300 / MW7
24257576
24261511
NQF
December 2011
K200 / 300 / MYD
24257581
24261510
NQG
January 2011
K200 / MYD / +Z49
24257580
24261509
NQG
January 2012
K200 / 300 / MW7
24257579
24261508
NQG
December 2011
K200 / 300 / MYD
/ -Z49
24252685
24261507
NQG
December 2011
K100 / M30
24252684
24261506
NQG
January 2011
K100 / MYC
RPO
Vehicle/
Transmission RPO
Page 8
April, 2013
Bulletin No.: 12-04-21-001B
Service Parts List
3216483
Magna Light Duty NQG/NQH/NP0 – First Design
Callout
Description
GM PN
Service Usage
1
Front Case Half Assembly w/gear (2) and ring 3)
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TSB/Document ID: 120421001B
Replacement Service Bulletin Number:
MFR Communication Date: 2013-04-01
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
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