1993 Chevrolet Suburban Owner's Manual - Page 289
1993 Chevrolet Suburban Manual
Page 289 highlights
Service & Appearance Care Front Axle When to Check and Change Lubricant: RefertotheMaintenanceScheduletodeterminehowoften to checkthe lubricantand when to changeit.See"ScheduledMaintenanceServices"in theIndex. How to Check Lubricant: PO231 If thelevel is belowthebottom of thefillerplughole,you'llneed to add (warm),add somelubricant. If thedifferentialisatoperatingtemperature to thebottom of the filler plug hole. enoughlubricanttoraisethelevel If thedifferential is cold,addenoughlubricant (12 mm)below thefillerplughole. to raisethelevel to 1/2 inch What to Use: Refer to theMaintenanceSchedule to determinewhatkindof use.See"RecommendedFluidsandLubricants"intheIndex. lubricant to Rear Axle When to Check and Change Lubricant: RefertotheMaintenanceSchedule to determinehowoftentocheckthe lubricantandwhen to changeit.See"RecommendedFluidsandLubricants" in theIndex. 6-24