Diagnosis and Testing - Power Transfer Unit

Inspection and Verification

1. 1
   Verify the customer concern.
2. 2
   Visually inspect for obvious signs of mechanical damage.

Visual Inspection Chart

• Power Transfer Unit
• Axle Shafts and CV Joints
• Driveshaft and Universal Joints
• Wheel and Tire Size
• Tire Size and Type Matching
• Tire Pressure

1. 1
   If an obvious cause for the observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
2. 2
   If the cause is not visually apparent, verify the symptom and refer to the Symptom Chart.

Symptom Chart

The diagnosis in this manual assumes a certain level of skill and knowledge of Ford-approved diagnostic procedures.
REFER TO: Diagnostic Methods (100-00 General Information, Description and Operation).

In most cases, the PCM sets a DTC to aid in diagnosis. Refer to the DTC. Before using the Symptom Chart, the Condition column lists the vehicle condition. The Possible Sources column lists the specific vehicle components that may cause the condition. The Action column lists the actions to perform to determine the cause of the condition. Each action lists components that may cause the system fault and the individual components of that system. Components are listed in disassembly order. Use the component list and the required actions to focus on the disassembly checks for the root cause of the concern.

Inspect the seal mating surface journal each time a seal is replaced. The mating part/journal must be replaced if any of the following conditions exist: Radial wear groove that can be felt when a fingernail is run across the area where the seal lip travels. Scratches, pits, abrasions, nicks, or other damage to the shaft under or adjacent to the seal lip. Discoloration or baked-on oil on the shaft where the seal lip travels. Shaft corrosion under or adjacent to the seal lip. Sharp edges or burrs on the shaft leading into the chamfer. NEVER use sandpaper to dress journals; replace the part.