Bulletin No.:

Service Bulletin

Date:

20-NA-156
February, 2022

TECHNICAL
Subject:

Rear Axle Clunk

Brand:

Model:

Chevrolet

Colorado

GMC

Canyon

Model Year:

VIN:

from

to

from

to

2015

2021

-

-

Engine:

Transmission:

-

-

Involved Region or Country

North America and Korea

Condition

Some customers may comment that a clunking noise can be heard from the rear axle
area when driving over railroad tracks and/or entering or exiting parking lots and
driveways.

Cause

This condition may be caused by excessive axle shaft end play.

Correction

With the aid of an assistant, apply the brake pedal while another technician lightly shake
the vehicle with a lateral force to the bed of the truck near the tail lamp area.
• If a clunk noise still persists while the brake is applied, inspect the leaf spring shackle
for excess movement or debris within leaf spring pads. Refer to 17-NA-394: Squeak,
Clunking Type Noise Heard From Rear of Vehicle.
• If clunk noise only occurs without the brake pedal applied, continue with this
procedure for excessive end play within the rear axle.

Copyright 2022 General Motors LLC. All Rights Reserved.

Page 2

February, 2022

Service Procedure
Perform endplay diagnostics:
1. Lift the vehicle.
2. Remove the rear wheels. Refer to Tire and Wheel
Removal and Installation in SI.
3. remove the rear calipers. Refer to Rear Brake
Caliper Replacement in SI.

Bulletin No.: 20-NA-156

endplay or higher. There must be at least
0.25mm (0.010”) of endplay on left had side to
not damage locker.
• If endplay is below 0.32mm (0.0126”), Service
C-locks may still be installed, however, if the
components (axle shaft and differential) are at
the low end of the tolerance, interference may
occur.
9. Repeat for opposite side.
10. Record endplay measurement.
Note: You do not need to pull the axle shafts out any
further than necessary to remove and replace the
C-locks.
⇒ If the endplay has been found out of
specifications noted above, proceed to the
next step.

5636028

4. Attach dial indicator to be able to measure
perpendicular to center of rotor face.
5. Push in axle shaft all the way by pushing on the
rotor face.
6. Zero out dial indicator at this stage.
7. Pull axle shaft outward all the way by pulling on the
rotor.
8. Record endplay measurement.
• If endplay measurement is at 0.32mm (0.0126”)
or greater, then service C-locks can be installed
without interference (exception detailed below).
– EXCEPTION – If it is a G80 Locking Rear
Axle, a C-lock can only be applied on the left
hand side if it measures 0.57mm (0.0224)

3686452

11. Remove the rear rotors (1). Refer to Rear Brake
Rotor Replacement in SI.

Bulletin No.: 20-NA-156

February, 2022

3825066

12. Remove the rear axle housing cover (1). Refer to
Rear Axle Housing Cover Replacement in SI.

Page 3

4663153

14. Remove the pin shaft (1).
15. Using care not to damage the axle seal, push the
axle shaft inwards.

4663151

13. Remove the lock pin bolt (1).

4998569

16. Remove the C-lock (1) from the rear axle.
17. Install new C-locks.
18. Install pin shaft.
⇒ Tighten pin lock bolt to specifications. Refer to
Fastener Specifications in SI.

Page 4

February, 2022

Bulletin No.: 20-NA-156

⇒ All C-clips may have yellow protective coating
⇒ If endplay exceeds 1.05mm (0.0413”), the end play
is out of spec. Please refer to Service Information
for further drive line diagnostic procedures.

Parts Information
Causal
Part

Part
Number

Qty

N/A

LOCK-R/AXL
SHF (LCV)

84878620

2

N/A

LOCK-R/AXL
SHF (LGZ
LWN LFX)

84878619

2

N/A

BOLT, R/AXL
HSG CVR

11546720

11 (8
for ZR2)

N/A

BOLT, R/AXL
HSG
CVR (STUD)

11549349

1 (4 for ZR2)

N/A

NUT, WRG
HARN BRKT

11546365

1 (4 for ZR2)

N/A

SAE 75W-90 Axle
Lubricant

19352759
(Canada
19352760)

2

N/A

BOLT, R/
CALIPER BRKT

11509377

4

4825501

19. Install the rear axle housing cover. Refer to Rear
Axle Housing Cover Replacement in SI.
⇒ Tighten new cover bolts (1, 2) to specifications.
Refer to Fastener Specifications in SI.
20. Install the rear brake rotors. Refer to Rear Brake
Rotor Replacement in SI.
21. Install the rear wheels. Refer to Tire and Wheel
Removal and Installation in SI.
22. Lower the vehicle.
Reference Information:
⇒ The production C-locks have a thickness spec of
5.18mm to 5.26mm (0.204” to 0.207”)
⇒ Service C-locks has a thickness spec between
5.42mm and 5.50mm (0.213” to .216”)

Description

Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.

Labor Operation

Description

Labor Time

3087158*

Diagnose Axle Noise and Replace C-Clips

1.1 hr

*This is a unique Labor Operation for Bulletin use only.

Version

2

Modified

Released November 05, 2020
Revised January 27, 2022 - Added the Rear Caliper Bracket Bolts to 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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