When you are defining a problem in the all wheel drive system, the following procedures should be followed. First, perform the visual inspections. When the visual inspections are complete and the problem is not fully understood, perform the operational checks. After the visual inspections and the operation checks are complete and the problem is not fully understood, perform the test procedures. The test procedures will help identify the problems in the all wheel drive system. When the problem is defined, perform the performance checks. The list of performance checks will show the probable cause of a known problem. Since there may be more than one cause for a problem, it may be necessary to perform more than one performance check. These inspections and these tests will help identify the causes that are most probable.