GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 SLS 🢒 Preface 🢒 Cautions and Notices 🢒 Vibration Analysis - Hub and/or Axle Input

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This test will determine the effect of turning input on the vibration.

    2.

  2. This test will determine the effect of an initial heavy torque load on the vibration.

    3.

  3. Damaged or worn wheel drive shafts may cause a noise or vibration that may be transferred into the passenger compartment.

    4.

  4. Damaged or worn wheel bearings may cause a noise or vibration that may be transferred into the passenger compartment.

    5.

  5. Damaged or worn suspension components may cause a noise or vibration that may be transferred into the passenger compartment.

    6.

  6. Damaged or worn engine, transmission, and/or exhaustion pipe support may cause a noise or vibration that may be transferred into the passenger compartment.

    7.

  7. Incorrect trim height may cause binding and/or interference between components that may produce a vibration.

Step

Action

Yes

No

Caution: Refer to Road Test Caution in the Preface section.

 

1

Has the Vibration - Road Testing table been performed?

Go to Step 2

Go to Vibration Analysis - Road Testing

2

  1. Drive the vehicle at the speed of vibration concern.
  2. Maintaining the concern speed, drive the vehicle with slow and smooth turns, first in one direction, then in the other direction.
  3. Observe the vehicle for changes in the vibration disturbance.
  4. Select a smooth, level surface, such as an empty parking lot or a remote road.
  5. Maintaining the vehicle at the concern speed as possible, drive the vehicle through sharp turns 360 degrees - first in one direction then in the other direction.
  6. Observe the vehicle for changes in the vibration disturbance.

Does the vibration change become worse or go away during these procedures?

Go to Step 3

Go to Step 6

3

Have you heard a clicking noise and/or feel a shudder during these procedures?

Go to Step 7

Go to Step 4

4

Have you heard rumbling noise during these procedures?

Go to Step 9

Go to Step 5

5

Have you heard a popping noise during these procedures?

Go to Step 10

Go to Step 14

6

  1. With the vehicle at a stand-still, apply the regular brake and place the transmission in the lowest forward gear.

    2. Important: Do not accelerate too much causing the drive wheels to squeal, slip, or hop. This will interfere with the test results.

  2. Release the regular brakes and accelerate to 32 km/h (20 mph).
  3. Observe the vehicle for changes in the vibration disturbance.

Have you felt a shudder or shaking during these steps?

Go to Step 7

Go to Vibration Diagnostic Aids

7

Inspect the wheel drive shafts for damage, abnormal, and/or excessive wear.

Does the test result show that one or more axle half shaft need to be replaced?

Go to Step 8

Go to Step 10

8

Based on the test result, replace the shaft. Refer to the corresponding procedures:

    • Wheel Drive Shaft Replacement - Front (Left)
         Wheel Drive Shaft Replacement - Front (Right)
    • Wheel Drive Shaft Replacement - Rear

Have you finished the replacement?

Go to Step 14

--

9

  1. Inspect the wheel bearings for wear and/or damage. Refer to Wheel Bearings Diagnosis .
  2. Replace any of the wheel bearings found to be worn and/or damaged. Refer to the corresponding procedure:

Did you find and correct the condition?

Go to Step 14

Go to Step 13

10

  1. Inspect the following suspension components for wear, damage, looseness, and/or possible contact with other vehicle components:
    2. • Struts/shock absorbers
    • Springs
    • Bushings
    • Insulators
  2. Replace any of the suspension components found to be worn, damaged, loose, and/or contacting with other vehicle components.

Did you find and correct the condition?

Go to Step 14

Go to Step 11

11

  1. Inspect the Powertrain Support for the following conditions:
    2. • Loose and/or missing fasteners
    • Improper alignment
    • Cracked, dry - rotted, and/or oil - soaked insulators
    • Twisted, broken, torn, and/or deformed brackets.
    • Bent, twisted, and/or deformed brackets.
  2. Replace the powertrain support as necessary. Refer to the following procedures:
    3. •  Engine Mount Bracket Replacement - Left Side for the 3.6L (LY7) engine
    •  Engine Mount Bracket Replacement - Right Side (rear wheel), for the 3.6L (LY7) engine
    •  Engine Mount Bracket Replacement - Left Side for the 4.6L (LH2) engine
    •  Engine Mount Bracket Replacement - Right Side (Rear wheel drive) for the 4.6L (LH2) engine
  3. Inspect the exhaust system components for the following conditions:
    4. • Loose and/or missing fasteners
       - Heat Shields
       - Joints and/or couplings, such as nuts, bolts, studs, clamps, straps.
       - Bracket and/or insulator mounting
    • Inadequate clearance to body or chassis components (the exhaust system in both COLD and HOT; transmission in NEUTRAL and REVERSE gear)
    • Improper alignment
    • Disconnect and/or missing insulators.
    • Cracked, dry-rotted, and/or oil-soaked insulators
    • Stretched, broken, torn, and/or collapsed insulators
    • Bent, twisted, cracked and/or deformed brackets.
  4. Repair, replace, and/or realign exhaust system components as necessary.

    5. Did you find and correct the condition?

Go to Step 14

Go to Step 12

12

Inspect the vehicle trim height and adjust as necessary. Refer to Trim Height Inspection .

Did you find and correct the condition?

Go to Step 14

Go to Step 13

13

Is the vehicle equipped with all-wheel drive?

Go to Vibration Analysis - Driveline

Go to Diagnostic Aids

14
  1. Install or connect all components that were removed or disconnect during diagnosis.
  2. Perform the Vibration - Road Testing . Refer to Vibration Analysis - Road Testing .

Is the vibration still present?

Go to Step 2

System OK