Service Bulletin

Bulletin No.:
Date:

03-00-91-001I
November, 2023

INFORMATION
Subject:

Vibration Analysis Worksheet

Models:

2024 and Prior GM Passenger Cars and Trucks
This bulletin has been revised to add the 2023-2024 Model Years and first Important
statement. Please discard Corporate Bulletin Number 03-00-91-001H.

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.
When diagnosing vibration concerns, use the following
worksheet in conjunction with the appropriate Vibration
Analysis-Road testing procedure in the Vibration
Correction sub-section in SI. FILL OUT ONLY THE
APPLICABLE PORTION OF THE WORKSHEET THAT
APPLIES TO THE VIBRATION / NOISE.
Refer to the appropriate section of SI for specifications
and repair procedures that are related to the vibration
concern.
Vibration Analysis Worksheet
VIN__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
Procedure Performed By:
Date:
Model:
Year:
Gear Ratio:
Odometer:
TAC Case #, if applicable:
Conditions During Road Test Procedures
As condition occurs: Engine RPM_____________
Vehicle Speed__________________
Vibration/Noise detected during the following road test procedures:
Engine RPM_______________ Vehicle Speed_______________
Slow Acceleration Test: Yes__________ No__________
Neutral Coast-Down Test: Yes__________ No__________
Downshift Test: Yes__________ No__________
Neutral Run-Up Test: Yes__________ No__________
Copyright 2023 General Motors LLC. All Rights Reserved.

Page 2

November, 2023

Bulletin No.: 03-00-91-001I

Vibration Analysis Worksheet
Brake Torque Test: Yes__________ No__________
Steering Input Test: Yes__________ No__________
Standing Start Acceleration (Launch Shudder) Test: Yes__________ No__________
Vibration/Noise Eliminated with TCC Commanded On: Yes__________ No__________
Vibration/Noise Eliminated with TCC Commanded Off: Yes__________ No__________
Vibration/Noise Duplicated on Hoist: Yes__________ No__________
When using the Pico Scope, always save the file. This will allow for review and help determine which vibration shows up the
most. Refer to Vibration Analysis - Road Testing (CH-51450-NVH Oscilloscope) in SI.
Pico Scope Readings
Refer to Oscilloscope Diagnostic Kit Description and Operation in SI for more detailed information.
Important: As a reminder, the CH-51450-TA183 Accelerometer incorporates a 3 m (9.8 ft) cord that allows the sensor to be
placed on virtually any component of the vehicle where a vibration concern is felt. i.e.: if the vibration complaint is from the seat
then place the sensor on the seat track, if the vibration complaint is from the steering wheel then attach the sensor to the steering
column. Ensure the Accelerometer is properly orientated. The typical areas are the seat track, the steering column or the
instrument panel. Locating the Accelerometer on additional areas (i.e. the right fender, left fender, right quarter panel, left quarter
panel, rear seat track, etc.) may also assist in determining the component causing the vibration/noise. The key is to look for the
same Hz reading with the greatest amplitude mg readings.
FILL OUT ONLY THE APPLICABLE PORTION OF THE WORKSHEET THAT APPLIES TO THE VIBRATION/NOISE:
Engine Readings:
Initial: E0.5:__________ E1:__________ E2:__________ E3:__________ E4:__________
Current: E0.5:__________ E1:__________ E2:__________ E3:__________ E4:__________
Prop/Driveshaft Readings:
Initial: P1:__________ P2:__________
Current: P1:__________ P2:__________
Driveshaft Runout:
Is runout within specification? Yes__________ No__________
Initial: Frt:__________ Center:__________ Rear:__________ Stub Shaft:__________
Current: Frt:__________ Center:__________ Rear:__________ Stub Shaft:__________
Pinion Flange Runout Reading:__________
Has a system balance been attempted: Yes__________ No__________ (If no, perform a System Balance)
Were the drums removed to system balance? Yes__________ No__________
Initial: HZ__________ Gs__________
Current: HZ__________ Gs__________
Hose clamps added: Yes__________ No__________
Prop shaft indexed? Yes__________ No__________
If a System Balance has been attempted but the vibration is still present or system balance was not able to be achieved, check
the ring gear backlash at each tooth of the ring gear. Note that excessive ring gear runout may result in a first order tire speed or
first order prop shaft speed concern.
Backlash at each tooth on the ring gear (readings should not vary more than 0.050 mm (0.002 in)):
Note: The Ring Gear teeth need to be dry.
1_______ 2_______ 3_______ 4_______ 5_______ 6_______ 7_______ 8_______ 9_______ 10_______
11_______ 12_______ 13_______ 14_______ 15________16______ 17_______ 18_______ 19_______ 20_______
21_______ 22_______ 23_______ 24_______ 25_______ 26_______ 27_______ 28_______ 29_______ 30_______
31_______ 32_______ 33_______ 34_______ 35________ 36_______ 37________ 38_______ 39_______ 40_______
Does the vehicle have any of the following components attached?
Pinion damper: Yes__________ No__________
Pinion flange damper: Yes__________ No__________
Exhaust damper: Yes__________ No__________
Initial: Front angle:__________ Center Angle:__________ Rear Angle:__________
Current: Front angle:__________ Center Angle:__________ Rear Angle:__________
Were shims added to the following?
Transmission/transfer case mount: Yes__________ No__________
Pinion nose (rear springs): Yes__________ No__________

Bulletin No.: 03-00-91-001I

November, 2023

Page 3

Vibration Analysis Worksheet
Center Support Mount: Yes__________ No__________
Tire Size and Brand:_____________________________________
Wheel/Tire Readings:
Initial: T1:__________ T2:__________ T3:__________ T4:__________
Current: T1:__________ T2:__________ T3:__________ T4:__________
Record wheel balance information below if available record weight information prior to balance and after balance.
Wheel/Tire balance
Right rear: Inner Weight:__________ Outer Weight:__________
Left rear: Inner Weight:__________ Outer Weight:__________
Right front: Inner Weight:__________ Outer Weight:__________
Left front: Inner Weight:__________ Outer Weight:__________
Aluminum Wheel/Tire Runouts on vehicle (max. 0.030 in (.762 mm))
Refer to the latest version of Corporate Bulletin Number 00-03-10-006 for tire radial force variation information.
Right rear: Inner lateral:__________ Center radial:__________
Left rear: Inner lateral:__________ Center radial:__________
Right front: Inner lateral:__________ Center radial:__________
Left front: Inner lateral:__________ Center radial:__________
Hub Mounting surface runouts (max. 0.005 in (0.132 mm))
Flange, right rear:__________ Hub, right front:__________
Flange, left rear:__________ Hub, left front:__________
Wheel stud runouts (max. 0.010 in (0.254 mm))
Flange, right rear:__________ Hub, right front:__________
Flange, left rear:__________ Hub, left front:__________
Sensor at Steering Column:
Initial: MPH/KPH:__________ Source/HZ:__________ mgs:__________
Current: MPH/KPH:__________ Source/HZ:__________ mgs:__________
Sensor at Drivers Seat Rail:
Initial: MPH/KPH:__________ Source/HZ:__________ mgs:__________
Current: MPH/KPH:__________ Source/HZ:__________ mgs:__________
Sensor at Passenger Seat Rail:
Initial: MPH/KPH:__________ Source/HZ:__________ mgs:__________
Current: MPH/KPH:__________ Source/HZ:__________ mgs:__________

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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