21-NA-270

Bulletin No.:
Service Bulletin
Date:
21-NA-270
August, 2022
INFORMATION
Subject:
Vibration Caused by Tires
Brand:
Model:
Chevrolet
Silverado 4500HD/
5500HD/6500HD
Involved Region or Country
Model Year:
from
to
2019
2022
VIN:
from
Engine:
Transmission:
to
United States
Additional Options (RPOs)
Condition
Some customers may comment on a vibration while driving.
Cause
The cause of the condition may be that the wheel and tire assemblies require Road Force
balance.
Verify the vibration is from the tires by using Pico scope (NVH) and attach to the
workorder.
Note: Before using the PICO drive the vehicle 15 to 20 minutes to help reduce the effect
of tire flat spots from sitting.
Correction
1. Lift and support the vehicle and remove the wheels, refer to Wheel Replacement.
in SI.
2. Separate the tire from the rim, using the hunter Road Balancer, the wheels should
be measured, and the high spots identified and marked. The front tires should have
a RFV less than 50 lbs.
3. Once these are measured the tire pairs should be reinstalled with the high spots
clocked 180 degrees from each other.
4. Before tire replacement tires follow the match mounting tire to the wheel assembles
called out in Bulletin 02-03-10-005C, record the findings.
Note: For wheel/tire assemblies above 75 lbs RFV clocking the high spots 180 degrees
may not provide enough reduction in vibration. Drive to determine, and replace rear tires
as needed to achieve required RFV per wheel tire assembly.
5. Record the RFV for each tire wheel assemble and attach to the work order.
• RF• LF• RRO• RRI• LRO• LRIIf a tire needs to replaced follow Bulletin 20-NA-159 for warranty Administration As only
the tires that are out of specification should be replaced.
Copyright 2022 General Motors LLC. All Rights Reserved.
Page 2
August, 2022
Bulletin No.: 21-NA-270
Service Procedure
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.
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
*8080688
Verify Vibration and Measure and Mark High Spot of the
Wheels
0.6 hr
Add
To Measure - Each Additional Wheel
0.3 hr
*This is a unique Labor Operation for Bulletin use only.
Version
2
Modified
Released November 19, 2021
Revised July 26, 2022– Added 2022 Model Year, added steps to Correction Section,
added Important statement under Service Procedure, and added Warranty Information
with Labor Operation.
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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