Buick Regal: Diagnostic Information and Procedures

SYMPTOMS - POWER TRANSFER UNIT CASE

Strategy Based Diagnostics

Review the system operations in order to familiarize yourself with the system functions. Refer to Power Transfer Unit Case Disassembled View, Power Transfer Unit Case Description and Operation, and Rear Drive Axle Description and Operation. All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system condition. The diagnostic flow is the place to start when repairs are necessary. For a detailed explanation, refer to Strategy Based Diagnosis.

Visual/Physical Inspection

• Inspect for aftermarket devices, which could affect the operation of the vehicle. Refer to Checking Aftermarket Accessories.
• Inspect the easily accessible or visible system components for obvious damage or conditions, which could cause the symptom.
• Inspect for the correct lubricant levels and the proper viscosities.
• Verify the exact operating conditions under which the concern exists. Note factors such as vehicle speed, road conditions, ambient temperature, and other specifics.
• Compare the driving characteristics or sounds, if applicable, to a known good vehicle and ensure you are not trying to correct a normal condition.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating properly.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• Diagnostic System Check - Vehicle.
• Noisy in Drive.
• Noisy When Coasting.
• Intermittent Noise.
• Constant Noise.
• Power Transfer Unit Case Leak Diagnosis.

NOISY IN DRIVE

NOISY WHEN COASTING

INTERMITTENT NOISE

CONSTANT NOISE

POWER TRANSFER UNIT CASE LEAK DIAGNOSIS

DEFINITION: A visible indication of an external fluid leak from the power transfer unit.

Review the Symptoms - Power Transfer Unit Case, and Power Transfer Unit Case Description and Operation and perform the necessary inspections. See below for suggested diagnostic method(s).

Special Tools

• GE-28431-6 Fluorescent Oil Dye
• GE-28428-E High Intensity Black Light Kit

For equivalent regional tools, refer to Special Tools.

Fluorescent Dye Method

1. Add GE-28431-6 Fluorescent dye to the transmission or power transfer unit to determine the source of the leak.

2. Operate the vehicle.

3. Inspect for the presence of dye within the oil leak using the GE-28428-E High Intensity Black Light Kit. A presence or non-presence of dye within the oil leak will indicate which component is the source of the leak.

Powder Method

CAUTION: Do not clean using brake cleaner or other reactive solvents as these solvents can damage rubber gaskets, seals and bushings.

1. Thoroughly clean the suspected leak area using a rag.

2. Apply an aerosol type leak tracing powder to the suspected leak area.

NOTE: Do not drive the vehicle on the freeway as this will splatter oil inhibiting leak diagnosis.

3. Operate the vehicle for 15 - 20 minutes under city driving conditions until normal operating temperatures are reached.

4. Shut OFF the engine.

5. Inspect the suspected leak area.

6. Trace the leak path through the powder in order to find the source of the leak.

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