1993 GMC Suburban Owner's Manual - Page 289

Hydrauk Chtch Grease Fitting A grease fitting is on the clutch housing for lubricating the clutch fork ball stud. See your Maintenance Schedule for when to lubricate the clutch housing. See "Recommended Fluids and Lubricants" in the Index for the proper lubricant to use. Be sure ne%to over-fill because you c ~ u l d damage your clutch. Most lubricantchecks in thissectionalsoapplytofour-wheel-drivevehicles. However,theyhavetwoadditionalsystemsthatneedlubrication. Transfer case When to Check LubrkW4t: Refer to theMaintenanceSchedule to determinehowoften to checkthe lubricant.See"PeriodicMaintenanceInspections" in theIndex. How to Check and Add Lubricant: I PO230 If the level is below the bottom of thefiller plug hole, you'll need to add somelubricant.Addenoughlubricant to raisethelevel to thebottom of the fillerplug hole. What to use: Refer to theMaintenanceSchedule to determinewhat kind of lubricantto use.See"RecommendedFluidsandLubricants" in theIndex. 6-23