Locking Rear Axle - GMC 1999 Sierra 1500 Pickup Owner's Manual

Features & Controls
Four-Wheel-Drive Vehicles Only: If your vehicle has four-wheel drive and is
equipped with a manual transmission, disregard the shift light when the
transfer case is in 4 LOW.
Shift Speeds-Manual Transmission
This chart shows when to shift to the next higher gear for best fuel economy.
MANUAL TRANSMISSION RECOMMENDED SHIFT SPEED
IN MPH (KMIH)
Engine
and VIN
45-50 25-40
50 40 15 4,3L V6
3 to 4
2 to 3 1 to 2 3 to 4 2 to 3 1 to 2
Code Trans.
Cruise Shift Speed
Acceleration Shift Speed
( 4
-
(64)
(40)
(24)
(K)
(72-80)
(40-64)
-
(80)
(64) (24)
5-Speed*
40
25 15 5.7L V8
- -
*
Transmission with L (low) gear only. L (low) is intended for heavy loads and
is not recommended for normal driving.
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TO1 61
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If your speed drops below 20 mph (32 km/h), or if the engine is not running
smoothly, you should downshift to the next lower gear. You may have to
downshift two or more gears to keep the engine running smoothly or for good
performance.
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If you skip more than one gear when you downshift, you could lose
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&
control of your vehicle: And you could injure yourself or others.
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Ju
skip more than one gear when you downshift, or if you race the
;,,,i n e when you downshift, you can damage the clutch or transmission.
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Locking Rear Axle
If you have this feature, your rear axle can give you additional traction on
snow, mud, ice, sand or gravel.
It
works like a standard axle most of the
time, but when one of the rear wheels has no traction and the other does,
the locking feature
will
allow the wheel with traction to move the vehicle.
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