1993 GMC Sonoma Owner's Manual - Page 270

Service & Appearance Care How to Check Lubricant: KO997 If the level is belowthebottom of thefiller plug hole,you'll need to add somelubricant. Add enoughlubricanttoraise the level tothebottom of the filler plug hole. What to Use: RefertotheMaintenanceScheduletodeterminewhat kind of lubricantto use.See"RecommendedFluids and Lubricants"intheIndex. Front Axle When to Check and Change Lubricant: Referto the MaintenanceScheduletodetermine how oftentocheckthe lubricant and when to changeit.See"ScheduledMaintenanceServices" the Index. in 6-22