File in Section:
Bulletin No.:

Service Bulletin

Date:

PI1354A
December, 2014

PRELIMINARY INFORMATION
Subject:

Information on Vibration Analysis and Diagnostic

Models:

2014 Chevrolet Silverado 1500
2015 Chevrolet Silverado
2014 GMC Sierra 1500
2015 GMC Sierra

Attention: This PI also applies to any of the above models that may be Middle East, Chile, Peru
and Thailand Export vehicles.
This PI has been revised to add the 2015 Model Year, update the Additional Notes for Testing
Table, edit the Check Pinion Flange Runout Measurement procedure and updated the
Example in the Backlash Adjustment Procedure. Please discard PI1354.

Training Available
US Courseware
Course

Delivery Platform

Course Description

Length

13042.14D1

Virtual Classroom Training (VCT)

Noise, Vibration and Harshness (NVH)
1

1.5 hrs

13042.14D2

Virtual Classroom Training (VCT)

Noise, Vibration and Harshness (NVH)

2.0 hrs

13042.14H

Hands-On Training (est. avl. December 2014)

Noise, Vibration and Harshness (NVH)

8.0 hrs

13042.12W

Web-Based Training

Noise, Vibration and Harshness (NVH)

2.0 hrs

13042.13V

Video On Demand (VOD)

PicoScope Noise, Vibration, and
Harshness Diagnostics Overview

15:05
minutes

13042.12W

Web-Based Training

Noise, Vibration and Harness

—

13042.05D1

Virtual Classroom Training (VCT)

Noise Vibration & Harshness - Session 1

—

13042.05D2

Virtual Classroom Training (VCT)

Noise Vibration & Harshness - Session 2

—

13025.16H

Hands-On Training

Vibration Diagnosis (2 day classroom
training)

—

13042.13V

Video On Demand (VOD)

PicoScope Noise, Vibration, and
Harshness Diagnostics Overview - VOD

—

GMCL Courseware

Condition/Concern
Some customers may comment about a vibration at speeds of 56-72 km/h (35-45 mph) or 96-120 km/h (60-70 mph),
which can be felt in either the seat or steering wheel.
The purpose of this bulletin is to outline the recommendations and procedures for diagnosing and repairing
vibrations caused by wheel and tire, axle components and/or propeller shafts.

Recommendation/Instructions
Important: The first step in determining the cause of the vibration is a test drive with the appropriate diagnostic
equipment installed on the vehicle. If the correct tools and procedures are not followed, an incorrect diagnosis will
result.
Full Size Truck Vibration Analysis:

4002193

1. Inspect the truck for any aftermarket equipment installations. For example: non factory tires, wheels and/or lift
kits or leveling kits – shims (1) installed as shown above. Aftermarket equipment does include running boards,
bug deflectors, and window shades, etc. Remove any aftermarket that might cause vibration transmission
paths.
2. Mark each tire valve stems location on the tire. This will be utilized to check for tire slippage on the rim.

4002206

3. Using a Pico Oscilloscope Diagnostic Kit, mount the PicoScope vibration sensor on one of the two locations
shown above.
Note: Only the use of the Pico Oscilloscope Diagnostic Kit with NVH should be utilized, available from GM Dealer
equipment (P/N 733–CH-51450). Previous vibrations tools are NOT recommended due to the types and frequencies
producing these vibrations.
• Seat Vibration – mount the sensor to the rear seat bracket (1).
• Steering Wheel Vibration – mount the sensor to the steering wheel bracket (2) under dash.
Note: In some cases, moving the sensor from a vertical position to a horizontal position may indicate higher
amplitude and may be beneficial to help in diagnosis.

4002212

4. This step should be only be used if the vibration can be felt while running the vehicle on the rack. Mount the
sensor on the steering shaft (1), under the hood as illustrated above.
5. Measure the vibration. Typically trucks should be driven in M5 to keep from switching in and out of active fuel
management (AFM).
Note: At the bottom of this bulletin is a required Vibration Diagnostic Worksheet that MUST be completed
and is required for the claim payment. Vibration Diagnostic must be retained by the dealership. This
worksheet is required to be filled out before calling TAC.
6. After the road test, verify that the tires have not slipped on the rim (step #2). If slippage has been found, correct
the condition prior to any other repair. Refer to the latest version of Corporate Bulletin Number 12-03-10-001:
Vibration Shortly After Tires are Mounted/Preventing Vibration from Wheel Slip (Tire Sliding on Wheel).
7. Once the condition has been duplicated on a test drive and the vibration readings have been recorded, bring the
vehicle back into the shop and test the vehicle on four jack stands or a suitable hoist. The hoist must support the
suspension at the same trim heights as the vehicle would normally sit on the road.
8. With the vehicle properly supported, bring the speed up to the complaint speed and verify that the previously
recorded vibration data matches current vibration data being displayed.
9. The test should be performed in both 2 wheel drive and 4 wheel drive, if equipped. If vibration can be duplicated
on the rack, the test should be performed a second time with the wheels and tire assemblies removed from the
vehicle and the wheel nuts installed to retain the brake discs and/or brake drums. If the vibration has been
eliminated with the wheel and tire assemblies removed, focus on the wheel and tire assemblies as the source of
the vibration. If the vibration is still present, focus on the vehicle driveline as the source of the vibration.
Additional Notes for Testing
• Phasing is typical on these tracks. Test drives should include many turns that can prevent phasing.
• Same test should be conducted after dealer correction to ensure vibration is eliminated throughout the entire
test repair phase.
Use the chart below to determine which type of vibration the truck has and what repair procedure should be utilized.
Type of Vibration

Go to Condition

1st Order Tire

1

1st Order Prop Shaft

2

2nd Order Prop Shaft

3

3rd Order Tire Combined with 1st Order Prop

4

Vibration Felt in 4 cylinder mode (AFM) –
V6 Engine Only

5

Vibration Felt at Idle Only

6*

*For rough idle and/or vibration at idle in gear – PIP5211: Rough Idle.
*For vibration related to AFM in 4 cylinder mode – refer to PIP5228: Vibration
During Active Fuel Management V4 Mode Operation 1200–1400 Engine RPM.

Important: Prior to any Road Force Balancing done with the Hunter 9700, please make sure that the wheel
assemblies pass the centering test, which is performed using the Hunter 9700 machine.

Condition 1: 1st Order Tire Suggestions (Freq 11-14 hz at 60 mph or 97 km/h)
Measurements
1. Remove the tire and wheel assemblies from the vehicle and perform the Road Force Variation (RFV)
measurement.
Important: Prior to taking any measurements, the assemblies MUST all pass a center check.
Note: Rule of Thumb for vibrations.
• Steering Wheel = Front Wheels
• Floor/Seat Track/Body = Rear Wheels
2. Document the before and after Road Force Variation (RFV) numbers on the vibration worksheet located at the
end of this bulletin.

Road Force Specifications
P-Metric tires on passenger cars

15 lbs (6.8 kg) or less

P-Metric tires on light trucks

15 lbs (6.8 kg) or less

LT - tires on light trucks

15 lbs (6.8 kg) or less

Note: These numbers are lower than what is currently published in service information as some vehicles react to
parts that are near the high limit. These numbers SHOULD NOT be used if you do not have a tire speed related
disturbance.
Repair:
• For any assembly that has an out of balance condition (greater than 0.25 oz), remove the weights and correct
the condition utilizing normal balancing techniques.
• For any assembly having RFV measurements beyond the specification above, vectoring the tire on the rim
should be utilized prior to tire replacement. If this does not bring the assembly within specification, the tire
should be replaced.
Additional Notes on Balancing:
• Always perform a centering check.
• The Hunter Balancer/Road Force Balancer should not be set to “Smart Weight.”
• All tires need to be balanced under 0.25 oz (both static and dynamic).
• When using the Hunter – Balancer/Road Force Balancer, removal and remounting to the tire balancer should
be performed to re-check balance and verify that results are repeatable to 0.25 oz or less.
• Check Wheel Runout.
Important: When replacing tires, the road force should be checked before a test drive and after a test drive (min of
10-15 miles or 16-24 km/h). Road force on new tires will change dramatically after being warmed up (as much as a
20 lb reduction). After the test drive, the tire’s road force should be checked. If acceptable RFV cannot be achieved,
first try vectoring the tire on the rim before an alternate tire is utilized. Also refer to the Information in the latest
version of Corporate Bulletin Number 13-03-10-002: Diagnostic Tips for Difficult to Resolve Tire/Wheel Vibration
Concerns. Some more information is needed on how to check the assemblies for 2nd, 3rd, and 4th order RFV.

Condition 2: 1st Order Prop Shaft (Freq 38-44 hz at 60 mph or 97 km/h)
Perform Propeller Shaft Runout Measurement (Refer to the SI Document ID# 2084709)
Specification

0.50”*

Actual Measurement
*For Best Result, the maximum runout should be under 0.20.” If over,
then replace the driveshaft.

Note: These numbers are lower than what is currently published in service information as some vehicles react to
parts that are near the high limit. These numbers SHOULD NOT be used if you do not have a propeller shaft speed
related disturbance.

Check Pinion Flange Runout Measurement
Special Tools:
• GE-7872 Magnetic Base Dial Indicator Set, equivalent
• GE-8001 Dial Indicator Set, or equivalent
For equivalent regional tools, refer to the Special Tools and Equipment in SI.
Note:
•
•
1.
2.
3.
4.

This measurement procedure is intended to measure propeller shaft runout for prop shaft systems with 2 or 3
U-joints only. This is not for prop systems with only 1 U-joint, or with only constant velocity (CV) joints, and/or
coupler assemblies.
When measuring runout of propeller shafts, do not include fluctuations on the dial indicator due to welds or
surface irregularities.
Raise and support the vehicle with the wheels free to rotate. Refer to the Lifting and Jacking the Vehicle in SI.
Place the transmission is NEUTRAL.
Clean the circumference of the propeller shaft of any debris and/or undercoating along the rear of the shaft,
where contact of the dial indicator will make to the propeller shaft.
Inspect the propeller shaft for dents, damage, and/or missing weights. Any propeller shaft this is dented or
damaged requires replacement.

734521

5. Mount the GE-7872 Magnetic Base Dial Indicator Set, or equivalent, or the GE-8001 Dial Indicator Set, or
equivalent, to the vehicle underbody or to a service stand positioned just clear of the U-joint yoke weld on the
prop shaft.
6. Rotate the drive pinion axle flange, torque tube input flange, transmission output, or transfer case output flange
by hand while take runout measurements of the prop shaft. The prop shaft will rotate more easily in one
direction than in the other. If necessary, the tire and wheel assemblies and even the brake caliper assemblies
can be positioned and supported aside, or the brake drums can be removed from the drive axle to provide axle
to provide easier rotation of the prop shaft.
7. Measure and mark the high spot of the propeller shaft. Mark the location of the propeller shaft to flange.
8. Rotate the propeller shaft 180 degrees from its original position on the flange.
9. Perform step six again.
10. If the high spot of the propeller shaft is in the same location as marked in the previous step and the
measurement exceeds the maximum prop shaft runout specified, the prop shaft requires replacement before
proceeding.
Note: This measurement is focused on pinion flange runout, it is NOT a complete measurement of the prop shaft
runout. To fully measure prop shaft runout, measurements must be taken at the front and middle of each prop shaft
segments.
11. If the high spot is in a different location, the runout is in the pinion flange or pinion. If this exceeds the maximum
allowable runout for the pinion flange, the source of the runout (usually the flange or the pinion itself) must be
found.

Perform Balance Measurement using “Adjustment Procedure Using Oscilloscope” (PicoScope) (Refer to the
SI Document ID# 3753593)
Specification

10 g-cm

Actual Measurement

For vehicles that are out of balance, perform a system balance. Using the two hose clamp method, the best driveline
balance results are obtained under 10 g-cm.
Suggestions:
1. Perform Runout Measurement.
2. Disassembly/reassembly rear yoke joint – checks for shift in U-joint.
3. Evaluation Drive.
4. Perform Runout Measurement.
5. Index 180.
6. Evaluation Drive.
7. Perform Runout Measurement.
8. Evaluation Drive.
9. Balance Shaft with PicoScope.
Diagnostic Aid:

4002784

•
•
•
•
•

Inspect the propeller shaft for dents or damage. There have been many cases of dented propeller shafts.
For 4WD Trucks, remove the rear propeller shaft, seal output shaft and drive the vehicle in 4WD. If the vibration
is gone, the rear prop shaft could be the problem.
For vehicles with a 3:08 with a one-piece steel shaft, this can be replaced with a one-piece aluminum one that
is utilized on all 3:42 and 3:73 ratios (K15543 and K15753 Models only).
PIP5140: Low Speed Vibration 30-35 mph (48-56 km/h).
Inspect the transmission output shaft bushing for irregular wear.

Condition 3: 2nd Order Prop Shaft (Normally a launch shudder or left under hard acceleration)