Strategy Based Diagnostics
Review the system in order to familiarize yourself with the system functions.
Refer to Differential Carrier Assembly Dissembled Views, Differential Carrier Assembly
Description, and Transfer Case Description procedures. All diagnosis on a vehicle
should follow a logical process. Strategy based diagnostics is a uniform approach
for repairing all systems. The diagnostics flow may always be used in order to resolve
a system problem. The diagnostic flow is the place to start when repairs are necessary.
For a detailed explanation, refer to Strategy Based Diagnostics procedure.
Visual/Physical Inspection
| • | Inspect for aftermarket devices, which could affect the operation of the
vehicle. Refer to Checking Aftermarket Accessories procedure in the Body service manual. |
| • | Inspect the easily accessible or visible system components for obvious
damage or a condition which could cause the symptom. |
| • | Check for correct lubricant level and proper viscosity. |
| • | Verify the exact operating conditions under which the concerns exist.
Note factors such as 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. |
| • | INSERT NOTICE:
Do not exceed more than 5 seconds
of parking brake application. RDM damage may result. |
| | Rear Axle activation
and operation may be checked by position the four wheels off the ground, starting
the vehicle, and selecting the drive position. A properly operating rear axle and
transfer case will rotate all four wheels at equal RPM. Fully apply the parking brake,
the rear will stop turning. Apply the throttle while watching the rear wheels. They
will rotate slightly as the driveline winds-up. This indicates the AWD is functioning. |
| • | Factors that may contribute to an inoperative rear axle include: |
| - | A mini spare or different size tires |
| - | A fluid over-temperature condition |
| - | A defective rear axle assembly |
| - | An inoperative transfer case assembly |
Intermittent
Test the vehicle under the same conditions that the customer reported in order
to verify the system is operating properly.
Noise Acceptability
A gear driven unit will produce a certain amount of noise. Some noise is acceptable
and audible at certain speeds, or under various driving conditions, such as a newly-paved
blacktop road. Slight noise is not detrimental to the operation of the axle and is
considered normal.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to
diagnose the symptom.
| • | Rear axle lubricant leak diagnosis |
