1993 GMC Suburban Owner's Manual - Page 357

6. AIR CLEANERFILTER REPLACEMENT* -Replaceatevery 30,000 miles (50 000 km)ormoreoftenunderdustyconditions. Ask yourdealer fortheproperreplacementintervalsforyourdrivingconditions. 7. FRONT WHEEL BEARING REPACK (2 WHEEL DRIVE ONLY) --Clean andrepackthefrontwheelbearingsateachbrakerelining,oratthe specifiedinterval,whichevercomesfirst. 8. TRAMSMISSBON SERVICE AutomaticTransmission -Changethetransmissionfluidand filter every 15,000 miles(25 000 km) forvehiclesunder8,600 GVWR or every 12,000miles (20 000 km)forvehiclesover8,600 GVWR if thevehicle of these conditions: ismainlydrivenunderoneormore Q In heavycitytraffic. Wheretheoutsidetemperatureregularlyreaches higher. 90°F (32°C) or * In hilly or mountainousterrain. * Frequenttrailerpulling. e Usessuchastaxi,police,deliveryorothercommercialservice. If thevehicle is notusedmainlyunderany of these conditions, change the fluid and filter-every 30,000 miles (50 000 km)forvehiclesunder 8600 8600 GVWR orevery 24,000 miles (40 000 km)forvehiclesover GVWR. See"AutomaticTransmissionFluid" in theIndexformore information. ManualTransmission -Transmission fluiddoesnotrequireperiodic changing. 9. CDRV SYSTEM INSPECTION* -ChecktheCrankcaseDepression RegulatorValveSystemforanyworn,pluggedorcollapsedhoses.Have thesystemcheckedasdescribed in theServiceManual. 10. FUEL FILTER REPLACEMENT" --Replacethefuelfilteratthespecified intervalorsooner if clogged. 11. SPARK PLUGS WEPLACEMENT* --Reglacesparkplugswiththetype listed in Section 6. See"SpecificationCharts" in theIndex. 12. SPARK PLUG WIRE INSPECTION* --Cleanwiresandinspectforburns, cracksorotherdamage.Checkthewirebootfitatthedistributorandat thesparkplugs.Replacewiresasneeded. *AnEmissionControlService 7-1 9