Bulletin No.: 12050B
Date: April 2014

Program Bulletin

CUSTOMER SATISFACTION PROGRAM
SUBJECT:

Rear Axle Grinding Noise, Vibration - Inspect Rear Axle

MODELS:

2011-2012 Chevrolet Express
2011-2012 Chevrolet Silverado, Suburban 2500 Series
2011-2012 GMC Savana
2011-2012 GMC Sierra, Yukon XL 2500 Series
Equipped with a 10.5" Rear Axle

The bulletin expiration date is being extended to April 30, 2015. Please discard all copies of
bulletin 12050A.

THIS PROGRAM IS IN EFFECT UNTIL APRIL 30, 2015
CONDITION
Certain 2011-2012 model year Chevrolet Express and GMC Savana vehicles, and Chevrolet
Silverado and Suburban, and GMC Sierra and Yukon XL 2500 Series vehicles, all equipped with
a 10.5" rear axle, may have a condition in which the rear axle right-hand side bearing adjuster
clip and bolt may come loose within the rear axle. If this occurs, a grinding noise and a vehicle
vibration would be noticeable when the vehicle is in motion. If the adjustor or bolt punctures the
differential cover pan, a fluid leak could develop. If enough fluid were to leak out, the driver may
hear increasing noise, additional vehicle vibration, and smell burnt axle lubricant. If the driver
ignores these warnings and continues to drive the vehicle, a slow loss of vehicle motion could
occur.
CORRECTION
Dealers are to inspect and, if necessary, repair the rear axle.

Copyright 2014 General Motors. All Rights Reserved.

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April 2014

Bulletin No.: 12050B

VEHICLES INVOLVED
All involved vehicles are identified by Vehicle Identification Number on the Investigate Vehicle
History screen in GM Global Warranty Management system. Dealership service personnel
should always check this site to confirm vehicle involvement prior to beginning any required
inspections and/or repairs. It is important to routinely use this tool to verify eligibility because
not all similar vehicles may be involved regardless of description or option content.
For dealers with involved vehicles, a listing with involved vehicles containing the complete
vehicle identification number, customer name, and address information has been prepared and
will be provided to US and Canadian dealers through the GM GlobalConnect Recall Reports, or
sent directly to export dealers. Dealers will not have a report available if they have no involved
vehicles currently assigned.
The listing may contain customer names and addresses obtained from Motor Vehicle
Registration Records. The use of such motor vehicle registration data for any purpose other
than follow-up necessary to complete this program is a violation of law in several
states/provinces/countries. Accordingly, you are urged to limit the use of this report to the
follow-up necessary to complete this program.
PART INFORMATION
Parts required to complete this program are to be obtained from General Motors Customer Care
and Aftersales (GMCC&A). Please refer to your “involved vehicles listing” before ordering parts.
Normal orders should be placed on a DRO = Daily Replenishment Order. In an emergency
situation, parts should be ordered on a CSO = Customer Special Order.
Part Number
03977326
26067159
88900401 - US
89021678 - CN

Description
LOCK, DIFF BRG ADJ NUT
GASKET, R/AXL HSG CVR
LUBRICANT, SYNTHETIC MULTI-PURPOSE (SAE
75W-90)

Quantity/Vehicle
1
1
3

Additional Parts Required if Differential is Repaired
Return the drive pinion, ring gear, differential side bearings, and pinion bearings to the Warranty
Parts Center (WPC) (U.S. and Canada only). PARTS MUST BE RETURNED TO THE WPC
UPON REQUEST FROM THE WPC.
Part Number
19210931
19210704
19210701
09436881
26064030
07451870
09414917
11515755

Description
GEAR KIT, DIFF RING & PINION (4.10 RATIO
GEAR KIT, DIFF RING & PINION (3.73 RATIO)
GEAR KIT, DIFF RING & PINION (3.54 RATIO)
BEARING, DIFF
SEAL, DIFF DRV P/GR
BEARING, DIFF DRV P/GR PILOT
BEARING, DIFF DRV P/GR OTR
BOLT, HEX,M8X1.25X16

Quantity/Vehicle
1
1
1
2
1
1
1
1

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April 2014

Bulletin No.: 12050B

SERVICE PROCEDURE
1.

Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in SI.

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2.

Remove the rear axle drain plug (1).

3.

Drain the lubricant into a suitable container.

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4.

Remove the park brake cable (2) from the center clip (1) on the axle and push the cable
over the spare tire to ensure it is out of the work area.

5.

Remove the caliper brake line from the clip and push the brake line gently toward the front
of vehicle to ensure it is out of the work area.

6.

Remove nuts holding the caliper line bracket to cover pan.

7.

Gently remove the caliper line bracket and push it up and away from the cover pan face.

8.

Remove the brake line clip bolt and the caliper brake line clip bolt.

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April 2014

Bulletin No.: 12050B

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9.

Remove the remaining cover pan bolts and remove the rear axle cover. Do NOT discard the
bolts.

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Adjuster Bolt (1) and (2) Clip Present. (B) Adjuster Bolt and Clip Not Present (3) and (4).

10. Determine if the passenger side (right) adjuster bolt (1) and clip (2) are present.


If the passenger side adjuster bolt and clip are present (A), remove the adjuster bolt
and clip. Discard only the clip. Refer to illustration. Proceed to Step 11.

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April 2014

Bulletin No.: 12050B

Note: Return the drive pinion, ring gear, differential side bearings, and pinion bearings to the
Warranty Parts Center (U.S. and Canada only). PARTS MUST BE RETURNED TO THE
WARRANTY PARTS CENTER UPON REQUEST FROM THE WARRANTY PARTS CENTER.


If the passenger side adjuster bolt and clip are NOT present (B), replace the drive
pinion, ring gear, differential side bearings, adjuster bolt and adjuster clip. Refer to
Differential Replacement (10.5 Inch Axle) in SI. Proceed to Step 14 after replacing the
drive pinion, ring gear, pinion bearings and differential side bearings. Refer to
illustration.

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Visually inspect the adjuster nut slot alignment (1) and then use a new adjuster clip (3) to verify slot
alignment. The adjuster clip (3) must be seated between the cap bolt ribs (2) and into the adjuster nut
holes as shown in illustration.

11. Inspect the adjuster nut slot location in reference to the cap bolt ribs (2).


If the adjuster nut slots are aligned (1) as shown in illustration, no adjustment is
required. Proceed to Step 13.



If the adjuster nut slots do NOT align, proceed to Step 12.

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Caution: If indexing the adjuster is required, the adjustment direction is critical. The passenger
side adjuster MUST be rotated in an upper direction to the nearest slot. If an upper direction is
NOT used, bearing preload is lost.

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April 2014

Bulletin No.: 12050B

12. Using J-24429 spanner (or equivalent) in the adjuster nut slot (1), rotate the adjuster nut
enough to center the clip between the cap bolt ribs. Only rotate the adjuster nut in an
upward direction.
Caution: To avoid damaging the differential, ensure the adjuster clip is aligned properly
BEFORE installing the adjuster bolt and clip.
13. Use a new adjuster clip (3) to verify alignment. The adjuster clip (3) must be seated
between the cap bolt ribs (2) and into the adjuster nut slots as shown in illustration.

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Note: If a differential replacement is required, a new bolt and a new adjuster clip are required. If
a differential replacement is NOT required, only a new adjuster clip is required.
14. Install a new adjuster clip and the bolt removed in Step 10 (1). Hand-tighten the bolt.
15. Tighten the bolt to 27 Nm (20 lb-ft).
16. Using a torque wrench, ensure that the driver side (left) adjuster clip and bolt are tightened
to 27 Nm (20 lb-ft).

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17. Remove old rear axle cover gasket material from rear axle housing and rear axle cover.
Ensure both surfaces are clean.
18. Apply Loctite 272 to the threads of all of the cover pan bolts.

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April 2014

Bulletin No.: 12050B

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19. Install cover on the axle.
19.1

Align a new cover pan gasket on the cover pan face.

19.2

Hand start two cover pan bolts to help keep the cover pan gasket aligned.

19.3

Put the park brake line clip and caliper brake line clip in position.

19.4

Install the remaining cover pan bolts.

19.5

Tighten the cover pan bolts to 40 Nm (30 lb-ft).

20. Insert park brake cable and caliper brake line back into clips.
21. Ensure the drain plug is clean. Remove any foreign material from the plug.

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22. Install drain plug.
23. Tighten drain plug to 33 Nm (24 lb-ft).
24. Remove fill plug.
25. Fill axle with synthetic lube until the lube starts to come out of the fill plug hole.

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April 2014

Bulletin No.: 12050B

26. Insert the fill plug.
27. Tighten the fill plug to 60 Nm (44 lb-ft).
COURTESY TRANSPORTATION – For US and Canada
The General Motors Courtesy Transportation program is intended to minimize customer
inconvenience when a vehicle requires a repair that is covered by the New Vehicle Limited
Warranties. The availability of courtesy transportation to customers whose vehicles are within
the warranty coverage period and involved in a product program is very important in maintaining
customer satisfaction. Dealers are to ensure that these customers understand that shuttle
service or some other form of courtesy transportation is available and will be provided at no
charge. Dealers should refer to the General Motors Service Policies and Procedures Manual for
Courtesy Transportation guidelines.
WARRANTY TRANSACTION INFORMATION
Submit a transaction using the table below.
Labor
Code
V2559
V2560

Description
Inspect Differential & Replace Clip (lock) Only
Inspect & Repair Differential
Add: Recondition Differential Case - Non Limited Slip
Add: Recondition Differential Case - Limited Slip

Labor
Time
0.7
5.0
0.3
1.4

CUSTOMER NOTIFICATION – For US and Canada
General Motors will notify customers of this program on their vehicle (see copy of customer
letter included with this bulletin).
CUSTOMER NOTIFICATION – For Export
Letters will be sent to known owners of record located within areas covered by the US National
Traffic and Motor Vehicle Safety Act. For owners outside these areas, dealers should notify
customers using the attached sample letter.
DEALER PROGRAM RESPONSIBILITY
All unsold new vehicles in dealers' possession and subject to this program must be held and
inspected/repaired per the service procedure of this program bulletin before customers take
possession of these vehicles.
Dealers are to service all vehicles subject to this program at no charge to customers, regardless
of mileage, age of vehicle, or ownership, through April 30, 2015.
Customers who have recently purchased vehicles sold from your vehicle inventory, and for
which there is no customer information indicated on the involved vehicle listing, are to be
contacted by the dealer. Arrangements are to be made to make the required correction
according to the instructions contained in this bulletin. A copy of the customer letter is provided
in this bulletin for your use in contacting customers. Program follow-up cards should not be
used for this purpose, since the customer may not as yet have received the notification letter.

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April 2014

Bulletin No.: 12050B

In summary, whenever a vehicle subject to this program enters your vehicle inventory, or is in
your facility for service through April 30, 2015, you must take the steps necessary to be sure the
program correction has been made before selling or releasing the vehicle.

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 tools,
equipment, 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 dealer for information on whether your vehicle may benefit from the information.

We Support
Voluntary Technician
Certification

Page 10

April 2014

Bulletin No.: 12050B
May 2012

Dear General Motors Customer:
We have learned that your 2011 or 2012 model year Chevrolet Express, Silverado, Suburban,
or GMC Savana, Sierra, Yukon XL vehicle, equipped with a 10.5 inch rear axle, may have a
condition in which the rear axle right-hand side bearing adjuster clip and bolt may come loose
within the rear axle. If this occurs, a grinding noise and a vehicle vibration would be noticeable
when the vehicle is in motion. If the adjustor or bolt punctures the differential cover pan, a fluid
leak could develop. If enough fluid were to leak out, you may hear increasing noise, additional
vehicle vibration, and smell burnt axle lubricant. If these warnings are ignored and the vehicle
continues to be driven, a slow loss of vehicle motion could occur.
Your satisfaction with your GM vehicle is very important to us, so we are announcing a program
to prevent this condition or, if it has occurred, to fix it.
What We Will Do: Your GM dealer will inspect and, if necessary, repair the rear axle. This
service will be performed for you at no charge until April 30, 2015. After that, any applicable
warranty will apply.
What You Should Do: To limit any possible inconvenience, we recommend that you contact
your dealer as soon as possible to schedule an appointment for this repair. By scheduling an
appointment, your dealer can ensure that any necessary parts will be available on your
scheduled appointment date.
If you have any questions or concerns that your dealer is unable to resolve, please contact the
appropriate Customer Assistance Center at the number listed below.
Division

Number

Chevrolet
GMC
Guam
Puerto Rico – English
Puerto Rico – Español
Virgin Islands

1-800-222-1020
1-800-462-8782
65-6267-1752
1-800-496-9992
1-800-496-9993
1-800-496-9994

Text Telephones
(TTY)
1-800-833-2438
1-888-889-2438

Courtesy Transportation: If your vehicle is within the New Vehicle Limited Warranty, your
dealer may provide you with shuttle service or some other form of courtesy transportation while
your vehicle is at the dealership for this repair. Please refer to your Owner Manual and your
dealer for details on Courtesy Transportation.
We sincerely regret any inconvenience or concern that this situation may cause you. We want
you to know that we will do our best, throughout your ownership experience, to ensure that your
GM vehicle provides you many miles of enjoyable driving.
Jim Moloney
General Director,
Customer and Relationship Services
12050