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speed will slowly increase to 1000 RPM after 2 minutes
of idle, if the following conditions are met:
•foot is off brake pedal and throttle pedal
•automatic transmission is in Park (P)
•vehicle speed is zero
•Applying the throttle will cancel fast idle
•If the engine is equipped with an aftermarket exhaust
brake (manual transmissions only), operating the ex-
haust brake at idle will greatly improve warm up rate
and will help keep the engine close to operating
temperature during extended idle.
Stopping The Engine
Idle the engine a few minutes before routine shutdown.
After full load operation, idle the engine 3 to 5 minutes
before shutting it down. This idle period will allow the
lubricating oil and coolant to carry excess heat away from the combustion chamber, bearings, internal components,
and turbocharger. This is especially important for turbo-
charged, charge air cooled engines.
NOTE:
During engine shutdown on vehicles equipped
with manual transmissions, it is normal for the diesel
engine to resonate heavily for a moment during engine
shut off. When the engine is connected to a manual
transmission, this resonance causes load gear rattle from
the transmission. This is commonly referred to as “shut
down rattle”. The manufacturer recommends performing
engine shut down with the clutch pedal pushed to the
floor (clutch disengaged). When engine shut down is
performed in this manner the rattle is reduced (not
eliminated).
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Driving
Condition Load Turbo-
charger
Temperature Idle Time
(min.)
Before
Engine
Shutdown
Stop and Go Empty Cool Less than
One
Stop and Go Medium One
Highway Speeds Medium Warm Two
City Traffic Maximum GCWR Three
Highway Speeds Maximum
GCWR Four
Uphill Grade Maximum
GCWR Hot Five
Engine Speed Control
CAUTION!
Prevent overspeeding the engine going down hill.
When descending steep grades, use a combination of
gears and service brakes to control vehicle/engine
speed. Overspeed can cause severe engine damage.
Operating Precautions
Avoid Overheating The Engine
The temperature of the coolant (a mixture of 50%
ethylene-glycol and 50% water) must not exceed the
normal range of the temperature gauge (240°F/116°C)
with a 16 psi (110 kPa) radiator cap.
Usually the coolant temperature indicated during opera-
tion will be to the left of center in the normal range of the
gauge.
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Avoid Low Coolant Temperature Operation
Continual operation at low coolant temperature below
the normal range on the gauge (140°F/60°C) can be
harmful to the engine. Low coolant temperature can
cause incomplete combustion which allows carbon and
varnish to form on piston rings and injector nozzles.
Also, the unburned fuel can enter the crankcase, diluting
the lubricating oil and causing rapid wear to the engine.
Cooling System Tips — Automatic Transmission
To reduce potential for engine and transmission over-
heating in high ambient temperature conditions, take the
following actions:
•City Driving —
when stopped, put transmission in neutral and increase
engine idle speed.
•Highway Driving —
reduce your speed.
•Up Steep Hills —
select a lower transmission gear, but try and keep the
torque converter locked.
•Air Conditioning —
turn it off temporarily.
Do Not Operate The Engine With Low Oil
Pressure
When the engine is at normal operating temperature, the
minimum oil pressures required are:
Idle 700 to 800 RPM ............... 10psi(69kPa)
Full speed and load .............. 30psi (207 kPa)
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WARNING!
It is dangerous to shift the selector lever out of “P” or
“N” if the engine speed is higher than idle speed. If
your foot is not firmly on the brake pedal, the
vehicle could accelerate quickly forward or in re-
verse. You could lose control of the vehicle and hit
someone or something. Only shift into gear when
the engine is idling normally and when your right
foot is firmly on the brake pedal.
“R” Reverse
Use this range only after the vehicle has come to a
complete stop. “N” Neutral
Shift to Neutral when the vehicle is standing for pro-
longed periods with the engine running. The engine may
be started in this range. Set the parking brake if you must
leave the vehicle.
“D” Drive
This position provides all forward gears, including 3rd
gear direct and 4th or 5th (if equipped) gear overdrive
(see Overdrive Operation). Use this range for most city
and highway driving.
“2” Second
Use this position for driving slowly in heavy city traffic
or on mountain roads where more precise speed control
is desirable. Use it also when climbing long grades, and
for engine braking when descending moderately steep
grades. To prevent excessive engine speed do not exceed
45 mph (72 km/h) in this range.
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toward you in one motion. Do not pull the lever sharply
left as you may shift accidentally into 2nd gear and
damage the transmission.
You should use 1st gear when starting from a standing
position if under heavy load or when pulling a trailer.
To shift into Reverse, come to a complete stop. Depress
the clutch and pause briefly to allow the gear train to
stop. Move the shift lever from the Neutral position
straight across and back into Reverse.
Never drive with your foot resting on the clutch pedal, or
attempt to hold the vehicle on a hill with the clutch pedal
partially engaged, as this will cause abnormal wear on
the clutch.Downshifting
Moving from a high gear down to a lower gear is
recommended to preserve brakes when driving down
steep hills. In addition, downshifting at the right time
provides better acceleration when you desire to resume
speed. Downshift progressively. Do not skip gears to
avoid overspeeding the engine and clutch. For accelera-
tion at speeds less than 15 mph (25 km/h), 2nd gear is
recommended.
CAUTION!
When descending a hill, be very careful to downshift
one gear at a time to prevent overspeeding the
engine which can cause valve damage.
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The 4-wheel-drive light (4WD), located in the instrument
cluster, alerts the driver that the vehicle is in 4-wheel
drive and that the front and rear driveshafts are locked
together. This light illuminates when the transfer case is
shifted to either the 4H or 4L positions. There is no light
for the 2H or N (Neutral) positions.
When operating your vehicle in 4L, the engine speed is
approximately three times that of the 2H or 4H positions
at a given road speed. Take care not to overspeed the
engine and do not exceed 25 mph (40 km/h).
Proper operation of 4-wheel-drive vehicles depends on
tires of equal size, type and circumference on each wheel.
Any difference will adversely affect shifting and can
cause damage to the transfer case. NOTE:
Do not attempt to make a shift while only the
front or rear wheels are spinning. The transfer case is not
equipped with a synchronizer and therefore the front and
rear driveshaft speeds must be equal for the shift to take
place. Shifting while only the front or rear wheels are
spinning can cause damage to the transfer case.
Because 4-wheel drive provides improved traction, there
is a tendency to exceed safe turning and stopping speeds.
Do not go faster than road conditions permit.
NOTE: Delayed shifts out of four-wheel drive may be
experienced due to uneven tire wear, low or uneven tire
pressures, excessive vehicle loading, or cold tempera-
tures.
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Shifting Procedure - Manually Shifted Transfer
Case
2H ⇔4H
Shifting between 2H and 4H can be made with the
vehicle stopped or in motion. If the vehicle is in motion,
shifts can be made up to 55 mph (88 km/h). With the vehicle in motion, the transfer case will engage / disen-
gage faster if you momentarily release the accelerator
pedal after completing the shift. Apply a constant force
when shifting the transfer case lever.
2H or 4H
⇔4L
With the vehicle rolling at 2 to 3 mph (3 to 5 km/h), shift
an automatic transmission to N (Neutral) or depress the
clutch on a manual transmission. While the vehicle is
coasting at 2 to 3 mph (3 to 5 km/h), shift the transfer
case lever firmly to the desired position. Do not pause in
transfer case N (Neutral).
NOTE: Pausing in transfer case N (Neutral) in vehicles
equipped with an automatic transmission may require
shutting the engine OFF to avoid gear clash while
completing the shift. If difficulty occurs, shift automatic
transmission to N (Neutral), hold foot on brake, and turn
engine OFF. Make shift to the desired mode.
Manual Transfer Case Shifter
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NOTE:Shifting into or out of 4L is possible with the
vehicle completely stopped, however difficulty may oc-
cur due to the mating clutch teeth not being properly
aligned. Several attempts may be required for clutch
teeth alignment and shift completion to occur. The pre-
ferred method is with the vehicle rolling 2 to 3 mph (3 to
5 km/h). Avoid attempting to engage or disengage 4L
with the vehicle moving faster than 2 to 3 mph (3 to 5
km/h).
NOTE: Do not attempt to shift to or from 4L while the
transmission is in gear or clutch is engaged.
Transfer Case Reminder Light
The four-wheel-drive operating light (4WD), located in
the instrument cluster, is used to alert the driver that the
front axle is fully engaged and all four wheels are
driving.
Electronically Shifted Transfer Case Operating
Information/Precautions–If Equipped
This is an electric shift transfer case and is operated by
the 4WD Control Switch (Transfer Case Switch), which is
located on the instrument panel.
Transfer Case Switch
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