Diesel Engine Exhaust Brake
If your vehicle has a Isuzu 6H Diesel Engine, it may
have an exhaust brake, which is located in the exhaust
system.
If your vehicle has a 6.6L DURAMAX
®6600 or
Caterpillar®Diesel Engine, it may have an exhaust
brake, which is controlled through the turbocharger.
The exhaust brake for both engines operates the same.
The exhaust brake switch
is located in the instrument
panel switchbank.
Push the bottom of the switch to turn the exhaust brake
on. When you push the top of the switch, the exhaust
brake will turn off.
There is an indicator light on the instrument panel
similar to the symbol on the switch, that comes on when
the exhaust brake is active. SeeExhaust Brake
Indicator Light on page 3-40for more information.While using the exhaust brake, the proper gear range
selection is important. The exhaust brake is most
effective if the gear range selected is the lowest possible
range that does not allow the engine rpm to go more
than 200 rpm above rated (full load) rpm. If you have a
Caterpillar
®Diesel Engine, do not exceed 2900 rpm.
If you have an Isuzu 6H Diesel engine, do not exceed
2550 rpm. If your vehicle has a DURAMAX
®6600
Diesel Engine, do not exceed 3600 rpm.
If your vehicle has an Allison
®1000/2200/2300/
2350/2500/2550 series automatic transmission and this
button is pressed, the transmission downshifts to a
factory default setting of third gear. To change
the default setting, or for more information on factory
default settings, contact your dealer/retailer for
assistance.
The accelerator and clutch pedals must be released in
order for the exhaust brake to engage. The exhaust
brake will automatically shut off when the antilock brake
system is active.
If your vehicle has a Caterpillar
®Diesel Engine or a
DURAMAX®6600 Diesel Engine, the exhaust brake will
become active in cruise control when you exceed the
set speed by 3 to 5 mph.
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Two-Speed Rear Axle
The Two-Speed rear axle lets the driver select Low
Range and High Range. Low Range provides good
starting torque and pulling power. When selecting High
Range the axle allows for higher road speed and
fuel economy.
For better performance during off-road or under a heavy
load, shift the axle into Low Range and then operate
the transmission normally.
For better performance on the highway, shift the axle to
High Range and operate the transmission normally.
High or Low Range can be used when additional shifts
between transmission gears is needed while driving
on grades and for better fuel economy.
Notice:Driving in Low Range above 50 mph
(80.5 kph) will damage driveline components. Drive
below 50 mph (80.5 kph) in Low Range.
If your vehicle has this feature, there is a label on the
headliner above the windshield or in another place near
the driver that shows how to use it. Be sure to follow
the directions carefully.
Two-Speed Rear Axle Shift Control
Operation
The rear axle shift control
switch for automatic and
manual transmissions
is located in the instrument
panel switchbank.
Press the bottom of the switch for High Range and the
top of the switch for Low Range. The switch indicator
light comes on when the High Range is selected.
Always start your vehicle in motion with the two-speed
axle in low range.
Shifting on a Downgrade
Do not shift the two-speed axle when driving on a
downgrade. The speed of the vehicle moving downhill
may make it hard to shift the axle into either Low or
High Range.
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Overdrive Defeat
If your vehicle has this feature, you can select not to
shift up to fifth gear. This is useful when towing or under
a heavy load.
The overdrive defeat
switch is located in the
instrument panel to
the right of the steering
column.
Press the switch to limit the transmission to fourth gear.
This will allow for fewer downshifts while pulling a
trailer or under a heavy load. The indicator light in the
switch comes on whenever overdrive defeat is active.
Manual Transmission Operation
Using the Clutch
When you are starting to move the vehicle, it is important
to begin with the engine speed at idle. Then start to
engage the clutch and listen for an engine speed drop of
about 100 rpm. At this point, the clutch is engaging, so
you should increase the engine speed and fully engagethe clutch. It is important not to increase the engine speed
sooner or before the clutch begins its engagement. If you
do, you can cause damage to your vehicle.
Double-Clutching
You must use the double-clutching method when you
shift an unsynchronized gear set. Disengage the clutch,
shift to NEUTRAL and engage the clutch. When
upshifting, slow the engine until the engine rpm and
road speed match. When downshifting, accelerate the
engine until the engine rpm and road speed match. Then
quickly disengage the clutch and move the shift lever
to the next gear position and engage the clutch.
Eaton®Fuller®Five and Six-Speed
Transmissions and TTC Spicer
Seven-Speed Transmissions
These transmissions have gears that automatically
synchronize when you shift up or down (except
FIRST (1) gear on the five-speed and seven-speed
transmission which is unsynchronized). Choose the gear
that will maintain the road speed you want while
keeping the engine above two-thirds of the governed
speed. When the engine speed drops below two-thirds
of the governed speed, shift into the next lower gear
before your engine begins to lug. When you shift down,
be sure to double-clutch if required.
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Eaton®Fuller®Nine and Ten-Speed
Non-Synchronized Manual
Transmissions
If your vehicle has one of these transmissions the
engine rpm and road speed must match when upshifting
and downshifting. The label above the windshield will
tell you the operating basics you need to know.
The following are driving tips.
•Always choose an initial starting gear suitable for
the load and terrain.
•Always use double-clutching procedures when
shifting.
•Never move the range shift lever to the LO speed
gear position after HI range preselection, or
anytime the transmission is in the HI range.
•Never move the range knob or lever with the shift
lever in NEUTRAL while the vehicle is moving.
•Never make a range shift while moving in
REVERSE (R).
Clutch Brake (Vehicles with
Non-Synchronized Transmission)
A clutch brake is used to stop transmission input shaft
rotation so that FIRST (1) or REVERSE (R) gear
selection can be initiated when the vehicle is at a
standstill and the engine is idling.
Press the clutch pedal all the way down to the floorboard
to apply the clutch brake.
When using the clutch brake, disengage the clutch
pedal and shift the transmission into either the initial
starting gear or REVERSE (R). If the tooth-butting
occurs between the clutching teeth, re-engage the clutch
while applying light pressure to the shift lever. This
will provide for a smooth shift into either FIRST (1) or
REVERSE (R) gear.
Notice:Using the clutch brake for shifting into any
gear other than FIRST (1) or REVERSE (R) may
cause premature wear of the clutch brake and make
gear shift effort more difficult. Do not use the
clutch brake for shifting after engaging FIRST (1) or
REVERSE (R).
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Locking Hubs
Turn the dial of the hublock (A) from the FREE position
to the LOCK position to lock the front axle.
Turn the dial of the hublock (A) from the LOCK position
to the FREE position to unlock the axle.
You do not have to back the vehicle up to disengage
the hublocks.If your vehicle has
four-wheel drive, the
transfer case knob is
located to the right of the
steering wheel on the
instrument panel. Use this
knob to shift into and
out of four-wheel drive.
An indicator light shows you which position the transfer
case is in. The indicator lights come on briefly when
you turn on the ignition and one stays on. If the lights do
not come on, you should take your vehicle to your
dealer/retailer for service. An indicator light flashes while
shifting the transfer case. It will remain on when the
shift is complete. If for some reason the transfer case
cannot make a requested shift, it returns to the last
chosen setting. Hublock Dial Location
Hublock Dial
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Notice:If your vehicle has an Allison®transmission
and you try to put the transmission in PARK (P)
while the transfer case is in Four-Wheel Low,
the transmission might not go into PARK (P) and
could damage your vehicle. When parking your
vehicle, make sure the transfer case is in Two-Wheel
High or Four-Wheel High.
NEUTRAL:Shift the vehicle’s transfer case to
NEUTRAL only when towing your vehicle.
Shifting Into Four-Wheel High
Turn the knob to four-wheel high. This can be done at
3 mph or less, while you are shifting out of Four-Wheel
Low. The indicator light flashes while shifting. It
remains on after the shift is complete. Be sure to lock
your front hubs.
Shifting Into Two-Wheel High
Turn the knob to Two-Wheel High. This can be done
at 3 mph or less, while you are shifting out of
Four-Wheel Low.
Shifting Into Four-Wheel Low
To shift to Four-Wheel Low, the vehicle’s engine must
be running and the vehicle must be stopped or
moving less than 3 mph (5 km/h) with the transmission
in NEUTRAL (N). The preferred method for shifting
into Four-Wheel Low is to have your vehicle moving
1 or 2 mph (1.6 to 3.2 km/h). Turn the knob to
Four-Wheel Low. You must wait for the Four-Wheel Low
indicator light to stop flashing and remain on before
shifting the transmission into gear. Be sure to lock the
front hubs.
Notice:Shifting the transmission into gear before
the Four-Wheel Drive Low indicator light has stopped
ashing could damage the transfer case. To help
avoid damaging your vehicle, always wait for the
Four-Wheel Drive Low indicator light to stop ashing
before shifting the transmission into gear.
If you turn the knob to Four-Wheel Low while your
vehicle is in gear and/or moving, the Four-Wheel Low
indicator light flashes for 30 seconds and does not
complete the shift unless your vehicle is moving less
than 3 mph (4.8 km/h) and the transmission is in
NEUTRAL (N). After 30 seconds, the transfer case
returns to the setting last chosen. If your vehicle is in
gear and moving less than 3 mph (4.8 km/h), the
transfer case shifts to Four-Wheel High.
2-35
Shifting Out of Four-Wheel Low
To shift from Four-Wheel Low to Four-Wheel High or
Two-Wheel High, your vehicle must be stopped or
moving less than 3 mph (5 km/h) with the transmission in
NEUTRAL (N) and the engine running. The preferred
method for shifting out of Four-Wheel Low is to have your
vehicle moving 1 or 2 mph (1.6 to 3.2 km/h). Turn the
knob to Four-Wheel High or Two-Wheel High. You must
wait for the Four-Wheel High or Two-Wheel High
indicator light to stop flashing and remain on before
shifting the transmission into gear.
Notice:Shifting the transmission into gear before
the Four-Wheel High or Two-Wheel High indicator
light has stopped ashing could damage the transfer
case. To help avoid damaging your vehicle, always
wait for the Four-Wheel High or Two-Wheel High
indicator light to stop ashing before shifting
the transmission into gear.
If the knob is turned to Four-Wheel High or Two-Wheel
High while your vehicle is in gear and/or moving, the
Four-Wheel High or Two-Wheel high indicator light
flashes for 30 seconds. It will not complete the shift
unless your vehicle is moving less than 3 mph (5 km/h)
with the transmission in NEUTRAL (N).
Shifting Into NEUTRAL
Before shifting the transfer case to NEUTRAL, first
make sure the vehicle is parked so that it will not roll.
1. Set the parking brake. SeeParking Brake (With
Hydraulic Brakes) on page 2-38orParking Brake
(With Air Brakes) on page 2-41for parking
brake apply procedure.
2. Start the vehicle.
3. Put the transmission in NEUTRAL (N).
4. Shift the transfer case to Two-Wheel High.
5. Turn the transfer case knob all of the way past
Four-Wheel Low and hold it there for a minimum of
10 seconds. The NEUTRAL indicator light comes on.
6. Shift the transmission to REVERSE (R) for
one second, then shift the transmission to
DRIVE (D) for one second.
7. Turn the ignition to OFF.
8. Place the transmission shift lever in PARK (P).
9. Turn the ignition to LOCK.
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Shifting Out of NEUTRAL
To shift the transfer case out of NEUTRAL, do the
following:
1. Set the parking brake. SeeParking Brake (With
Hydraulic Brakes) on page 2-38orParking Brake
(With Air Brakes) on page 2-41for parking
brake apply procedure.
2. Apply the regular brake pedal.
3. Turn the ignition to ON/RUN with the engine off.
4. Put the transmission in NEUTRAL (N).
5. Turn the transfer case knob to the desired shift
position (Two-Wheel High, Four-Wheel High,
Four-Wheel Low).
6. After the transfer case has shifted out of NEUTRAL,
the indicator light goes out.
Notice:Driving with the parking brake on can
overheat the brake system and cause premature
wear or damage to brake system parts. Verify that
the parking brake is fully released and the brake
warning light is off before driving.7. Release the parking brake.
8. Start the engine and shift the transmission lever to
the desired position.
Excessively shifting the transfer case into or out of the
different modes can cause the transfer case to enter the
shift protection mode. This protects the transfer case from
possible damage and only allows the transfer case to
respond to one shift per 10 seconds. The transfer case
can stay in this mode for up to three minutes.
Parking
{CAUTION:
If you do not park your vehicle properly, it can
roll. If you have left the engine running, it can
move very quickly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on level ground, follow the
steps below.
2-37