SB-10044384-7564

GM Bulletin No.: 12082
Date: May 2012

Service Bulletin

SERVICE UPDATE
SUBJECT:

Service Update for Inventory Vehicles Only
Rear Differential Module Seal Leak
Expires May 31, 2013

MODELS:

2012 Buick LaCrosse
2012 Cadillac SRX

This service update involves vehicles in dealer inventory only and will expire May 31,
2013.

PURPOSE
This bulletin provides a service procedure to replace the clutch piston seal in the rear differential
module on certain 2012 model year Buick LaCrosse and Cadillac SRX all wheel drive vehicles.
The internal clutch piston seal on these vehicles may leak and cause the Service Rear Wheel
Drive message to illuminate and set a C0407-64 DTC.
This service procedure should be completed on involved vehicles currently in dealership
inventory as soon as possible but no later than May 31, 2013, at which time this bulletin
will expire.
VEHICLES INVOLVED
All involved vehicles are identified by VIN in the Global Warranty Management System
Investigate Vehicle History Application. Dealership technicians 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.

Update Bull
to the GlobalConnect message (Canada) used to release this bulletin.

Copyright 2012 General Motors. All Rights Reserved.

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May 2012

Bulletin No.: 12082

PART INFORMATION
Parts required to complete this service update are to be obtained from General Motors
Customer Care and Aftersales (GMCC&A
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

Description

22956728

PISTON KIT,L/SLIP DIFF CLU

88863349 - US
88863350 - CN

LUBRICANT,DIFFERENTIAL(CLUTCH)
(will service 4 vehicles)

88900401 - US
89021678 - CN
88900330 - US
00992694 - CN

LUBRICANT,SYNTHETIC MULTIPUPOSE(LUBRICANT,GR SYNTHETIC,SAE 75W-90)

1

LUBRICANT,LIMITED-SLIP DIFFERENTIAL

1

Quantity/Ve
hicle
1
As Needed
(Submit as
Net Item)

SERVICE PROCEDURE
Caution: It is very important to observe maximum cleanliness when working on the differential
clutch. Dirt particles can seriously damage the function and service life of the differential clutch.
1.

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

2.

Drain the rear differential fluid.

3.

Remove the rear axle assembly from the vehicle. Refer to the Differential Carrier Assembly
Replacement procedure in SI.

4.

Place the rear differential assembly on a clean work bench.

Warning: The hydraulic pressure in the differential clutch is very high. To prevent personal
injury, wait for at least 10 minutes before removing any parts from the differential clutch.
5.

Remove the limited slip differential clutch low and high pressure pipes from the differential
clutch.

6.

Remove the electrical connector from the limited slip differential valve and remove the
harness from the clip.

7.

Remove the limited slip differential clutch bolts (Qty: 6).

8.

Remove the limited slip differential clutch from the differential carrier assembly.

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May 2012

Bulletin No.: 12082

2789536

9.

Remove the retaining ring that secures the differential clutch pack to the clutch housing.

2789542

2789543

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May 2012

Bulletin No.: 12082

10. Remove the differential clutch pack from the clutch housing. Hold the housing in one hand
and flip over to allow the clutch pack to fall into the other hand.

2789545

2806109

11. Apply compressed air to the low pressure pipe connector port to release the piston from the
differential clutch housing.

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May 2012

Bulletin No.: 12082

12. Remove the eLSD clutch piston from the housing.

2789546

Note: If the piston spring is removed, ensure proper orientation when reinstalling. Spring fingers
must be positioned as shown above.
13. Install the new eLSD clutch piston into the housing. Push down to seat.
14. Reinstall the differential clutch pack into the housing.
15. Reinstall the retaining ring that secures the differential clutch pack to the clutch housing.
16. Remove the low and high pressure pipe connectors from the limited slip differential clutch.
Discard the connectors and pipe spring clips.
17. Install the NEW low and high pressure pipe connectors and spring clips to the limited slip
differential clutch.
Tighten
Start by hand then tighten the connectors to 7 N·m (62 lb in).
18. Reinstall the limited slip differential clutch to the differential carrier assembly.

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May 2012

Bulletin No.: 12082

2806114

19. Reinstall the limited slip differential clutch bolts (Qty: 6).
Tighten
Tighten the bolts in proper sequence to 30 N·m (22 lb ft).
20. Reinstall the limited slip differential clutch low and high pressure pipes to the differential
clutch.

2806112

21. Reinstall the electrical connector to the limited slip differential valve and harness to the clip.
Route the electrical harness under the pressure lines as shown.

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May 2012

Bulletin No.: 12082

2806115

22. Remove the TTD clutch cover fill plug (2) and add 140 ml (0.15 qts) of eLSD clutch
lubricant. Install the fill plug.
Tighten
Tighten to 14 N·m (10 lb ft).
23. Install the rear axle assembly to the vehicle. Refer to the Differential Carrier Assembly
Replacement procedure in SI.
24. Refill the differential rear axle. Refer to the Differential Rear Axle Lubricant Level Inspection
in SI.
25. Lower the vehicle. Refer to Lifting and Jacking the Vehicle in SI.
26. Start the vehicle and allow running for 5 minutes at idle.
27. In PARK, cycle the throttle from idle to wide open throttle briefly 5 times, waiting a minimum
of 30 seconds between each WOT cycle to cycle solenoids to purge air.
28. With the engine running, observe the scan tool rear limited slip differential clutch pump
motor current parameter. The parameter display should be above 2.5A when the pump is
on. If the current is below 2.5A, then shut the vehicle off and recheck the level by
performing Steps 29 through 33.
29. To stabilize the clutch oil level, let the vehicle rest 10 minutes with the ignition off.
30. Raise the vehicle and support the vehicle.
31. Remove the differential clutch cover plug (2) and recheck the differential clutch fluid level.
32. The eLSD clutch fluid should be level with the bottom of the eLSD clutch cover plug hole
(2). If the eLSD clutch is overfilled, drain out fluid until it is at the proper level. Add fluid
through the vent opening (1) if the eLSD clutch is low on fluid.
33. Install the TTD clutch cover plug (2) and re-tighten to 14 N·m (10 lb ft).
34. Lower the vehicle.
35. Vehicles will also require a calibration update to the clutch control module (CCM). Follow SI
and TIS2WEB instructions to reprogram the CCM with the latest calibration available
through TIS2WEB.
36. Drive the vehicle 6 miles (10 km) to confirm that the DTC does not reset.

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May 2012

Bulletin No.: 12082

WARRANTY TRANSACTION INFORMATION
Submit a transaction using the table below.
Labor
Code
V2579
*

Description
Replace Clutch Piston (inc. reprogramming)

Labor Time
4.6

Net
Item
*

d represent the actual sum total of the current
GMCC&A Dealer net price for differential (clutch) lubricant needed to perform the required
repairs, not to exceed $11.12 USD, $13.75 CAD, plus applicable Mark-Up or Landed Cost
(for Export).

DEALER PROGRAM RESPONSIBILITY
Dealers must take the steps necessary to ensure that the service update correction has been
made to all involved vehicles in dealer inventory before selling or dealer-trading the vehicle, but
no later than May 31, 2013.

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.

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