Begin the system diagnosis by reviewing Differential Carrier Assembly Disassembled Views, Differential Carrier Assembly Description, Locking Differential Description and Operation, and Transfer Case Description and Operation. Reviewing the description and operation information will help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the description and operation information will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Rear Differential Carrier in order to identify the correct procedure for diagnosing the system and where the procedure is located.