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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 227 (Vibration Diagnosis And Correction) >> Diagnostic Information and Procedures >> Vibration Analysis - Driveline

Vibration Analysis - Driveline

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

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Step Action Yes No
1 Has the Vibration Analysis - Road Testing table been completed? Go to Step 2  Go to Vibration Analysis - Road Testing (EL-38792-A Electronic Vibration Analyzer) , or Vibration Analysis - Road Testing (CH-51450-NVH Oscilloscope) 
2 Did you duplicate a vibration concern that occurs only during heavy acceleration at launch? Go to Step 3  Go to Step 4 
3 Is the vehicle equipped with a solid drive axle and at least 1 universal joint in the propeller shaft system? Go to Step 26  Go to Step 4 
4 Did you record frequency data from the CH-51450-NVH  Oscilloscope Diagnostic Kit (w/NVH) or the EL-38792-A  Electronic Vibration Analyzer (EVA) 2, during the Vibration Analysis - Road Testing procedure? Go to Step 5  Go to Step 10 
5 Based on the Vibration Analysis - Road Testing table, is the concern first order, sixth order, or a slightly higher multiple of first order driveline related? Go to Step 6  Go to Step 8 
6 Is the vehicle equipped with a rear mounted transaxle assembly? Go to Step 7  Go to Step 11 
7 Inspect the drive axle for proper operation. Refer to the Drive Axle diagnosis information.
Did you find and correct a condition?		 Go to Step 31  Go to Step 2 
8 Based on the Vibration Analysis - Road Testing table, is the concern second order driveline related? Go to Step 9  Go to Step 10 
9 Does the vehicle driveline contain any universal joints? Go to Step 26  Go to Vibration Diagnostic Aids 
10 Based on the Vibration Analysis - Road Testing table, is the concern a noise that is not felt? Go to Vibration Diagnostic Aids  Go to Vibration Analysis - Road Testing (EL-38792-A Electronic Vibration Analyzer) , or Vibration Analysis - Road Testing (CH-51450-NVH Oscilloscope) 
11
  1. Inspect the following components for wear and/or damage:
    • Inspect the propeller shafts for dents, damage, missing weights, and/or undercoating.
    • Inspect the universal joint, or joints, if equipped, for excessive wear, looseness, and/or damage.
    • Inspect the propeller shaft constant velocity (CV) joint, or joints, if equipped, for excessive wear, looseness, and/or damage.
    • Inspect the propeller shaft coupler assembly, or assemblies, if equipped, for excessive wear, looseness, and/or damage.
    • Inspect the propeller shaft support bearing, if equipped, for damaged rubber components, worn bearings, looseness, and/or a deformed or cracked bracket.
    • Inspect the drive axle mounts, if equipped, for excessive wear, looseness, and/or damage.
  2. Replace any of the components found to be worn or damaged.
Did you find and correct a condition?		 Go to Step 31  Go to Step 12 
12 Attempt to duplicate the vibration in the stall. Vibration in Service-Stall Test (Non-Torque Sensitive)
Were you able to duplicate the vibration?		 Go to Step 16  Go to Step 13 
13 Perform the Vibration in Service-Stall Test (Torque Sensitive). .
Were you able to duplicate the vibration?		 Go to Step 14  Go to Vibration Diagnostic Aids 
14 Is the vehicle 4WD system? Go to Step 15  Go to Vibration Diagnostic Aids 
15
  1. Remove the rear propeller shaft.
  2. Perform the Vibration in Service-Stall Test (Torque Sensitive). .
Is the vibration still present?		 Go to Transfer Case diagnosis information Go to Drive Axle diagnosis information
16 Was the vibration most evident under the transmission or the transfer case, if equipped? Go to Step 17  Go to Step 20 
17
  1. If the driveline joint at the transmission or transfer case is a universal joint, measure the propeller shaft runout at the end closest to the transmission or transfer case. Propeller Shaft Runout Measurement 
  2. Replace components as necessary.
Did you find and correct a condition?		 Go to Step 19  Go to Step 18 
18
  1. Inspect the powertrain mounts for the following:
    • Loose and/or missing fasteners
    • Improper alignment
    • Cracked, dry-rotted, and/or oil-soaked insulators
    • Twisted, broken, torn, and/or collapsed insulators
    • Bent, twisted, and/or deformed brackets
  2. Replace the powertrain mounts as necessary.
Did you find and correct a condition?		 Go to Step 19  Go to Step 20 
19 Perform the Vibration in Service-Stall Test (Non-Torque Sensitive). .
Is the vibration still present?		 Go to Step 20  Go to Step 31 
20
  1. Inspect the propeller shaft universal joint, or joints, if equipped, for excessive wear, looseness, and/or damage.
  2. Inspect the propeller shaft CV joint, or joints, if equipped, for excessive wear, looseness, and/or damage.
  3. Inspect the propeller shaft support bearing assembly, if equipped, for damaged rubber components, worn bearings, and/or a deformed or cracked bracket.
  4. If the driveline joint at the drive axle is a universal joint, measure the runout of the complete propeller shaft, or shafts. Propeller Shaft Runout Measurement 
  5. Replace components as necessary.
Did you find and correct a condition?		 Go to Step 21  Go to Step 22 
21 Perform the Vibration in Service-Stall Test (Non-Torque Sensitive). .
Is the vibration still present?		 Go to Step 22  Go to Step 31 
22
  1. Measure the runout of the drive axle pinion input flange or shaft:
  2. For a direct-mount drive axle, inspect the mounts and/or bushings for excessive wear, looseness, and/or damage.
  3. Replace excessively worn or damaged components as necessary.
Did you find and correct a condition?		 Go to Step 23  Go to Step 24 
23 Perform the Vibration in Service-Stall Test (Non-Torque Sensitive). .
Is the vibration still present?		 Go to Step 24  Go to Step 31 
24 Re-index the propeller shaft. Perform the following steps:
  1. Raise and support the vehicle.
  2. Mark the position of the propeller shaft to both the transmission or transfer case output shaft flange, and the drive axle input flange.
  3. Remove the propeller shaft.
  4. Rotate the propeller shaft 45 degrees to both of the flanges.
  5. Reinstall the propeller shaft.
  6. Attempt to duplicate the vibration in the stall. Vibration in Service-Stall Test (Non-Torque Sensitive).

Was the vibration reduced or eliminated?		 Go to Step 31  Go to Step 25 
25 Return the propeller shaft to it's original position and balance the propeller shaft. Driveline System Balance Adjustment 
Were you able to balance the driveline system?		 Go to Step 31  Go to Vibration Diagnostic Aids 
26
  1. Inspect the following components for wear and/or damage:
    • Inspect the propeller shafts for dents, damage, missing weights, and/or undercoating.
    • Inspect the universal joint, or joints for excessive wear, looseness, and/or damage.
    • Inspect the propeller shaft support bearing, if equipped, for damaged rubber components, worn bearings, looseness, and/or a deformed or cracked bracket.
  2. Replace components as necessary.
Did you find and correct a condition?		 Go to Step 31  Go to Step 27 
27 Is the drive axle a direct-mount? Go to Step 29  Go to Step 28 
28
  1. Measure the vehicle trim height.
  2. Adjust the vehicle trim height if necessary. Trim Height Inspection
Did you find and correct a condition?		 Go to Step 31  Go to Step 29 
29
  1. Measure the propeller shaft angles. Driveline Working Angles Measurement 
  2. If necessary, adjust the propeller shaft angles. Driveline Working Angles Adjustment 
Did you find and correct a condition?		 Go to Step 31  Go to Step 30 
30
  1. Inspect the propeller shafts for proper phasing. Propeller Shaft Phasing Inspection 
  2. If necessary, correct the propeller shaft phasing. Propeller Shaft Phasing Correction 
Did you find and correct a condition?		 Go to Step 31  Go to Vibration Diagnostic Aids 
31
  1. Install or connect any components that were removed or disconnected during diagnosis.
  2. Perform the Vibration Analysis - Road Testing (EL-38792-A Electronic Vibration Analyzer) , or Vibration Analysis - Road Testing (CH-51450-NVH Oscilloscope) .
Is the vibration still present?		 Go to Step 5  System OK
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