20NA030

Bulletin No.:
Service Bulletin
Date:
20-NA-030
December, 2020
TECHNICAL
Subject:
Rear Air Suspension Inoperative
Model Year:
Brand:
Model:
Chevrolet
Silverado 4500HD,
5500HD and 6500HD
from
to
2019
2020
VIN:
from
to
Engine:
Transmission:
Involved Region or Country
North America
Additional Options (RPOs)
G40 (SUSPENSION REAR-12,000 LB, AIR)
GP1 (SUSPENSION REAR-13,500 LB, AIR)
GP8 (SUSPENSION REAR-15,500 LB, AIR)
Condition
Some customers may comment that the rear of the truck sits low, or air suspension will
not properly inflate.
Cause
This condition may be caused by the rear air spring coming off the lower mount when
lifting/removing weight off rear axle.
Correction
If it has been verified that the rear air spring has come off the rear mount, replace both
rear air springs and the shock absorbers.
Service Procedure
Refer to Air Spring Replacement in SI.
Refer to Rear Shock Absorber Replacement (With Air
Springs) in SI.
Parts Information
Causal
Part
Description
Part
Number
Qty
X
SPRING, RR AIR
19407642
2
N/A
ABSORBER,
RR SHK
19408176
2
Copyright 2020 General Motors LLC. All Rights Reserved.
Page 2
December, 2020
Bulletin No.: 20-NA-030
Description
Labor Time
8000021
Rear Air Spring Replacement - Both Sides
8044751
Rear Shock Absorber Replacement - Both Sides
Use the Published Labor
Operations Time
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Version
1
Modified
Released November 30, 2020
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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