Strategy Based Diagnostics
Review the system operations in order to familiarize yourself with the system functions. Refer to
Differential Carrier Assembly Description. 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 the easily accessible or visible system components for obvious damage or conditions, which could cause the symptom. |
| • | Check for the correct lubricant level and the proper viscosity. |
| • | 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 make sure you are not trying to correct a normal condition. |
| • | Inspect for all-wheel drive activation and operation. |
| | Factors that may contribute to an inoperative rear differential include: |
| - | Differential inoperative due to antilock brake system (ABS) function |
| - | Inoperative engine control module (ECM) and/or wiring system |
| - | A mini-spare or different size tire installed |
| - | A fluid over-temperature condition |
| - | An inoperative or "stuck" clutch pump check valve |
| - | A defective rear differential assembly |
| - | An inoperative transfer case assembly |
| • | Sometimes it might be difficult to judge whether the noise is coming from the propeller shaft or rear differential carrier assembly. Refer to
Symptoms - Propeller Shaft. |
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:
