GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

Check the flywheel ring gear for damage, unusual wear or a bent flywheel.

Shim the starter as required, if necessary.

In order to add pinion to ring gear clearance a full size shim must be used. Do not shim only one starter mounting bolt. There are three shims available in different shapes (for clearance), all are 1 mm thick.

Step

Action

Yes

No

1

Did you review the engine electrical operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Engine Electrical

2

Start the engine.

Does the starter operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Start the engine while listening to the starter motor turn.

Is there a loud "whoop" (it may sound like a siren if the engine is revved while the starter is engaged) after the engine starts, but while the starter is still held in the engaged position?

Go to Step 6

Go to Step 4

4

Do you hear a "rumble", a "growl", or, in some cases, a "knock" as the starter is coasting down to a stop after starting the engine?

Go to Step 7

Go to Step 5

5

When the engine is cranked, do you hear a high-pitched whine after the engine cranks and starts normally?

(This is often diagnosed as a starter drive gear hang-in or a weak solenoid.)

Go to Step 8

Go to Step 7

6

Inspect the flywheel ring gear for the following:

    • Chipped gear teeth
    • Missing gear teeth
    • milled teeth

Does the flywheel have damaged teeth or is bent?

Go to Step 9

Go to Step 10

7

  1. Remove the starter motor. Refer to Starter Motor Replacement
  2. Inspect the starter motor bushings and clutch gear.

Does the clutch gear have chipped or milled teeth or worn bushings?

Go to Step 10

Go to Step 9

8

Shim the starter motor away from the flywheel by adding shims one at a time, between the starter motor and the engine block.

Flywheel runout may make this noise appear to be intermittent.

Did you complete the repair?

Go to Step 11

--

9

Replace the flywheel. Refer to Engine Flywheel Replacement in Engine Mechanical - 2.5L (LB8) and 3.0L (L46).

Did you complete the replacement?

Go to Step 11

--

10

Replace the starter motor. Refer to Starter Motor Replacement .

Has the noise stopped?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2