GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 TrailBlazer - 2WD 🢒 General Information 🢒 Vibration Diagnosis and Correction 🢒 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 exhaust mounts 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: One or more of the following guidelines may apply when performing specific required tests in the work stall:

   • When a test requires spinning the drive wheels with the vehicle jacked up, adhere to the following precautions:
      - Do not exceed 56 km/h (35 mph) when spinning one drive wheel with the other drive wheel stopped. This limit is necessary because the speedometer indicates only one-half the actual vehicle speed under these conditions. Personal injury may result from excessive wheel spinning.
      - If all of the drive wheels are spinning at the same speed, do not exceed 112 km/h (70 mph). Personal injury may result from excessive wheel spinning.
      - All persons should stay clear of the rotating components and the balance weight areas in order to avoid possible personal injury.
      - When running an engine in the repair stall for an extended period of time, use care not to overheat the engine and the transmission.
   • When a test requires jacking up the vehicle and running with the wheels and brake rotors removed, adhere to the following precautions:
      - Support the suspension at normal ride height.
      - Do not apply the brake with the brake rotors removed.
      - Do not place the transmission in PARK with the drive axles spinning.
      - Turn Off the ignition in order to stop the powertrain components from spinning.
   • When running an engine in the work stall, use the exhaust removal system to prevent breathing dangerous gases.

 

1

Has the Vibration Analysis - Road Testing table been performed?

Go to Step 2

Go to Vibration Analysis - Road Testing

2

  1. Operate the vehicle at the speed of the vibration concern.
  2. While maintaining the concern speed, drive the vehicle through slow, sweeping 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. While maintaining the vehicle at the concern speed if 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.

Did the characteristics of the vibration change significantly (become worse or go away) during these steps?

Go to Step 3

Go to Step 6

3

Did you hear a clicking noise and/or feel a shudder during these steps?

Go to Step 7

Go to Step 4

4

Did you hear a growling noise during these steps?

Go to Step 9

Go to Step 5

5

Did you hear a popping noise during these steps?

Go to Step 10

Go to Step 13

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 to the point of causing the drive wheels to squeal, slip or hop - this would obscure the results of the test.

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

Did you feel a shudder or shaking during these steps?

Go to Step 7

Go to Vibration Diagnostic Aids

7

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

Did the inspection indicate that one or more of the wheel drive shafts needs to be replaced?

Go to Step 8

Go to Step 10

8

Replace the wheel drive shaft(s) as indicated by the results of the inspection. Refer to Wheel Drive Shaft Replacement in Wheel Drive Shafts.

Did you complete the replacement?

Go to Step 13

--

9

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

Did you find and correct a condition?

Go to Step 13

Go to Vibration Diagnostic Aids

10

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

Did you find and correct a condition?

Go to Step 13

Go to Step 11

11

  1. Inspect the powertrain mounts for the following:
    2. • 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 powertrain mounts as necessary. Refer to the following procedures:
    3. •  Engine Mount and Bracket Replacement - Left Side in Engine Mechanical - 4.2L
    •  Engine Mount and Bracket Replacement - Right Side in Engine Mechanical - 4.2L
    •  Transmission Mount Replacement in Automatic Transmission - 4L60-E
  3. Inspect the exhaust system components for the following:
    4. • Loose and/or missing fasteners
       - Heat Shields
       - Joints and/or couplings
       - (Nuts, bolts, studs, clamps, straps)
       - Bracket and/or insulator mounting
    • Inadequate clearance to body and/or chassis components (with the exhaust system both COLD and HOT; in NEUTRAL, FORWARD and REVERSE gears)
    • Improper alignment
    • Disconnected and/or missing insulators
    • Cracked, dry-rotted, and/or oil-soaked insulators
    • Stretched, twisted, broken, torn, and/or collapsed insulators
    • Bent, twisted, cracked, and/or deformed brackets
  4. Repair, replace, and/or realign exhaust system components as necessary.

Did you find and correct a condition?

Go to Step 13

Go to Step 12

12

Inspect the vehicle trim height and adjust as necessary. Refer to Trim Height Inspection in Suspension General Diagnosis.

Did you find and correct a condition?

Go to Step 13

Go to Vibration Diagnostic Aids

13
  1. Install or connect any components that were removed or disconnected during diagnosis.
  2. Perform the Vibration Analysis - Road Testing table. Refer to Vibration Analysis - Road Testing .

Is the vibration still present?

Go to Step 2

System OK