2003 GMC Sierra 1500 Pickup Owner's Manual - Page 130

Shifting from 2Hl or 4HI to 4LO To shift from 2HI or 4HI to 4L0, the vehicle must be stopped or moving less than 3 mph (4.8 km/h) with the transmission in NEUTRAL (N). The preferred method for shifting into 4LO is to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press and release the 4LO switch. You must wait for the 4L0 indicator light to stop flashing and remain illuminated before shifting your transmission into gear. If the 4LO switch is pressed when your vehicle is in gear and/or moving, the 4L0 indicator light will flash for 30 seconds and not complete the shift unless your vehicle is moving slower than 3 mph (4.8 km/h) and the transmission is in NEUTRAL (N). The transfer case will shift to 4HI while waiting to complete the shift. If the 4HI switch is pressed when your vehicle is in gear and/or moving, the 4HI indicator light will flash for 30 seconds but will not complete the shift unless the vehicle is moving slower than 3 mph (4.8 km/h) and the transmission is in NEUTRAL (N). Shifting into NEUTRAL To shift the transfer case to NEUTRAL, first make sure the vehicle is parked so that it will not roll: 1. Set the parking brake. 2. Start the vehicle or turn the ignition to RUN. 3. Connect the vehicle to the towing vehicle. 4. Put the transmission in NEUTRAL (N). 5. Shift the transfer case to 2HI. Shifting from 4L0 to 4HI or 2HI To shift from 4LO to 4HI or 2H1, your vehicle must be stopped or moving less than 3 mph (4.8 km/h) with the transmission in NEUTRAL (N). The preferred method for shifting out of 4LO is to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press and release the 4HI switch. You must wait for the 4HI indicator light to stop flashing and remain illuminated before shifting your transmission into gear. 6. Simultaneously press and hold the 2HI and 4L0 buttons for 10 seconds. The red NEUTRAL light will come on when the transfer case shift to NEUTRAL is complete. 7. Shift the transmission to REVERSE (R) for one second, then shift the transmission to DRIVE (D) for one second. 8. Turn the ignition to OFF. 9. Place the transmission shift lever in PARK (P). IO. Release the parking brake prior to towing. 2-43