1999 GMC Sierra 1500 Pickup Owner's Manual - Page 91

D (Third Gear) D when Thisislike OD, butyounevergointoOverdrive.Youshoulduse towingatrailer,carrying a heavyload,drivingonsteephills,orforoff-road driving. 2 (Second Gear) Thispositiongivesyoumorepowerbutlowerfueleconomy. You canuse 2 onhills. It canhelpcontrolyourspeed as you godownsteepmountain roads,butthenyouwouldalsowant to useyourbrakes off and on. If youmanuallyselect 2, thetransmission will drive in second gear.Youmay to use this feature for reducing torque to therearwheelswhenyouaretrying startyourvehiclefromastoponslipperyroadsurfaces. 1 (First Gear) 2. Thispositiongivesyouevenmorepower(butlowerfueleconomy)than You canuse it onverysteephills,or in deepsnowormud. If theselector lever is putin 1, thetransmissionwon'tshiftintofirstgearuntilthevehicleis goingslowlyenough. NWTIGE If yourrearwheelscan'trotate,don'ttry to drive. This might happen if you were stuck in very deep sand or mud or were up against a . solid AWZ ...object. You could damage your transmission. ._,, . ,