Four-Wheel Drive - GMC 1999 Sierra 1500 Pickup Owner's Manual

Features & Contmls
Four- Wheel Drive
CAUTION
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It can be dangerous to get out of your vehicle if the shift lever -is not
fully in P (Park) with the parking brake firmly set. Your vehicle can
roll. Don't leave your vehicle when the engine is running unless you
have
to.
If you've left the engine running, the vehicle can 'move
suddenly. You or -others could be injured. To be sure your vehicle
won't move, even when you're on fairly level ground, always set your
parking brake and move the shift lever to P (Park).
If you have four-wheel drive and your transfer case is in N (Neutral),
your vehicle will be free to roll, even if your shift lever is in P'(Park).
So, be sure the transfer case is in a drive gear-not in N (Neutral).
Follow the proper steps to be suce your vehicle won't move. See
"Shifting Into P (Park)" in the Index.
I f you are parking on a hill, or i f you're pulling a trailer, also see
"Parking 'on Hills'' or "Towing a Trailer" in this section.
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If your vehicle has four-wheel drive, you can send your engine's driving power
to all four wheels for extra traction. To get the most satisfaction out of
four-wheel drive, you must be familiar with it's operation. Read the part that
follows before using four-wheel drive. You should use 2H for most normal
driving conditions.
Rear-wheel antilock brakes do not work when you shift into four-wheel drive.
Your regular brakes will still work. When you shift back into two-wheel drive,
your rear-wheel antilock brakes will take over again.
I
NOTICE
Driving in the 4H or 4L positions for a long time on dry or wet pavement
could shorten the life of your vehicle's drivetrain.
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