1997 GMC Sonoma Owner's Manual - Page 73

To shift into or out 4LO: of Electronic Transfer Case(If Equipped) ... 1. The vehicle must be moving less than 3 mph (4.8 km) with the transmission in NEUTRAL (N) for an automatic transmission. For a manual transmission, the clutch pedal must be engaged. The preferred method for shifting into 4LO is to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). 2. Press the transfer case shift button and shift in one continuous motion. Don't pause in N SET PARK BRAKE as you shift into or outof 4L0, oryour gears could clash. Remember that driving in 4HI or 4LOmay reduce fuel economy. Also, driving in four-wheel drive on dry pavement could causeyour tires to wear faster and make your transfer case harder to shiftand reduce powertrain longevity. ..., ^ I . ,, ., If your four-wheel-drive vehicle has the electronic transfer case, the transfer case switches are above the radio controls. Use these switches to shift into and out of four-wheel drive. You can choose among three driving settings: 2HI: This setting is for driving in most street and highway situations. Your front axle is not engaged in two-wheel drive. When this lamp is lit, it is about one-half as bright as the others. 4HI: This setting engages your front axle to help drive your vehicle. Use 4HI when you need extra traction, such as on snowy or icy roads, or in most off-road situations. 2-25