Begin the system diagnosis by reviewing the Differential Carrier Assembly Disassembled Views and the Differential Carrier Assembly Description in Rear Drive Axle, and Transfer Case Description and Operation in Transfer Case - NVG 900. 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 Drive Axle in order to identify the correct procedure for diagnosing the system and where the procedure is located.