18NA377

File in Section:
Bulletin No.:
Service Bulletin
Date:
18-NA-377
December, 2018
TECHNICAL
Subject:
Front Seat Lateral Movement and/or Click Type Noise While Driving
Attention: This bulletin replaces 3 PI’s. Please discard PI1183A, PI1376 and PIT5542.
Model Year:
VIN:
Brand:
Model:
from
to
Cadillac
Escalade
Models
2015
2019
Chevrolet
Silverado
1500
2014
2014
GMC
Sierra 1500
2014
2014
Chevrolet
Silverado,
Suburban,
Tahoe
2015
2018
GMC
Sierra,
Yukon
Models
2015
2018
Chevrolet
Silverado
LD,
Silverado
2500/3500,
Suburban,
Tahoe
2019
2019
GMC
Sierra
Limited,
Sierra 2500/
3500, Yukon
Models
2019
2019
Involved Region or Country
from
Engine:
Transmission:
All
All
to
North America, N.A. Export Regions
Additional Options (RPOs)
Condition
Customer may comment that the driver and/or passenger seat lower cushion exhibits
excessive lateral seat movement combined with a clunk type feeling, or generates a click
type noise.
This condition occurs when the seat is occupied and the vehicle is being driven on roads
with multiple curves or during low speed maneuvers.
Cause
The cause of the condition may be movement between the seat pan front pivot points and
the seat frame pivot bar. The plastic attachment points may “stick” then “slip” creating the
condition.
There may also be excessive clearance between the power seat vertical adjuster
actuator and the attachment point on the seat frame.
Correction
Use the steps in the Service Procedure below to lubricate the front seat pan pivot points,
add a lateral retainer to the outboard pivot, and install a shim clip between the power seat
vertical adjuster actuator and the seat frame (if required) to the affected seat(s).
Copyright 2018 General Motors LLC. All Rights Reserved.
Page 2
December, 2018
Service Procedure
Bulletin No.: 18-NA-377
Note: It is NOT necessary to completely remove the
seat cover and pad, only the side and front retainers
need to be released. The rear of the cover can remain
attached.
• Move the seat into a position where the front
and inboard side of the seat cover can be
accessed.
• Disengage the front, left and right J-channel
retainers from the seat cushion frame as shown
above.
4025118
1. Partially disengage the front seat cushion outer
finish cover.
• Only remove the front seat cushion outer finish
cover front fastener (1) as show above.
• Disengage the cover by pulling upward near the
retainer clip locations.
Caution: The front seat cushion outer finish cover rear
fastener is still installed, take caution when disengaging
the cover.
4024923
3. Remove the four screws that attach to the two pivot
blocks to the seat pan.
Note: Lift the seat pan to provide additional working
access.
4025189
2. Partially remove the forward half of the lower seat
cushion cover and pad on the affected seat.
3967501
Important: DO NOT attempt to remove the pivot
blocks from the seat. Possible damage to the pivot
blocks may result.
4. Slide the two pivot blocks to the center of the seat,
to allow for applying grease to the pivot bar.
Bulletin No.: 18-NA-377
December, 2018
Page 3
3619960
5. Using a small brush, apply GM Super Lube, GM P/
N 12371287 (In Canada, use 10953437) as shown.
Ensure the complete contact surface is coated.
3619963
7. Align the holes in the seat pan with the holes in the
pivot blocks.
3619964
4025748
6. Move the pivot blocks back out to their original
position.
8. Hand start the four screws; Do NOT tighten.
Page 4
December, 2018
4649728
Note: For some 2016 and newer model years, an
updated seat frame design incorporates welded
brackets (1) to the seat frame pivot bar, on each side of
the white guide block. This helps to reduce the
excessive lateral seat movement.
Important: Regardless of the model year, in some
cases, even with the updated seat frame design, there
still could be excessive clearance between the welded
brackets (1) and the white guide block. This will cause
excessive lateral seat movement.
9. If the excessive lateral seat movement is verified,
the front seat lateral retainer (GM PN 13405675)
can be installed to correct this condition.
Important: The installation procedure of the lateral
retainer, will depend on which seat frame design the
vehicle has. In order to be able to correctly install the
front seat lateral retainer on the new updated seat
frame design, a modification MUST be done.
10. Inspect the seat frame for existence of the added
welded brackets (1):
• If NO welded brackets are visible on the seat
frame, jump ahead to step #12 and install the
lateral retainer.
• If the welded brackets are visible on the seat
frame, continue on to step #11, which includes
a modification step.
Bulletin No.: 18-NA-377
4649794
11. It will be necessary to remove plastic material from
the top side of the guide end of the lateral retainer
to enable installation. Using a grinder, or similar
tool, remove approximately 10 mm (0.40 in) of
material (1) from the top, down to the mold seam
line (2), as shown above.
4031854
12. Install the lateral retainer to the outboard end of the
pivot bar as shown above. Ensure the retainer is
fully seated around the pivot bar and on the guide
block.
Note: The lateral retainer can only be installed
one way.
• The double slotted side (1) of the lateral retainer
attaches to the pivot block.
• The single slotted side (2) of the lateral retainer
attaches to the end of the pivot bar.
Bulletin No.: 18-NA-377
December, 2018
4031857
Page 5
4031883
18. Locate the power seat vertical adjuster actuator
attachment to the seat frame.
19. Inspect for the presence of the shim clip (1) as
shown.
4032701
13. Install a nylon tie strap around the retainer as
shown above. Trim the excess tie strap material.
14. Tighten the four screws for the pivot blocks.
15. Operate the front of the seat up and down to verify
the welded bracket does not interfere with the front
seat lateral retainer.
16. Wipe off any excess lubricant.
17. Re-install the forward portion of the lower seat
cushion cover on the affected seat. Ensure all side
and front retainers are fully engaged to the seat
frame.
3619968
20. If a shim clip is not present, install the shim clip (1)
as shown.
Note: It may be necessary to slightly spread the
bracket on the seat frame with a large screwdriver to
allow clearance for the clip.
Page 6
December, 2018
Bulletin No.: 18-NA-377
Parts Information
Causal
Part
Description
Part
Number
Qty
Front Seat Lateral
Retainer
13405675
1 per seat
Shim Clip
13594989
1 per seat
GM Super Lube 3
oz. Tube
12371287
(In Canada,
use
10953437)
As Required
N/A
Warranty Information
For vehicles repaired under the Bumper-to-Bumper
coverage (Canada Base Warranty coverage), use the
following labor operation. Reference the Applicable
Warranties section of Investigate Vehicle History (IVH)
for coverage information.
Labor
Operation
Description
Labor
Time
7080188*
Lubricate Front Seat Pivot
Points, Install Lateral Retainer
and Install Seat Actuator
Shim Clip.
0.6 hr
Add
Perform procedure to both front
seats (If Needed)
0.4 hr
* This is a unique Labor Operation for Bulletin use only.
Version
1
Modified
Released December 17, 2018
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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