
DRIVE
This range should be used for most city and highway
driving. It provides the smoothest upshifts and down-
shifts, and the best fuel economy. The transmission
automatically upshifts through underdrive first, second,
and third gears, direct fourth gear and overdrive fifth and
sixth gears. The DRIVE position provides optimum driv-
ing characteristics under all normal operating conditions.
When frequent transmission shifting occurs (such as
when operating the vehicle under heavy loading condi-
tions, in hilly terrain, traveling into strong head winds, or
while towing heavy trailers), use the Electronic Range
Select (ERS) feature (refer to “Electronic Range Select
(ERS)” in this section) to select a lower gear range. Under
these conditions, using a lower gear range will improve
performance and extend transmission life by reducing
excessive shifting and heat buildup.If the transmission operating temperature exceeds nor-
mal operating limits, the powertrain controller will
modify the transmission shift schedule and expand the
range of torque converter clutch engagement. This is
done to prevent transmission damage due to overheat-
ing.
If the transmission becomes extremely hot, the “Trans-
mission Temperature Warning Light” may illuminate and
the transmission may downshift out of Overdrive until
the transmission cools down.
NOTE:
Use caution when operating a heavily loaded
vehicle at low speeds (such as towing a trailer up a steep
grade, or in stop-and-go traffic) during hot weather. In
these conditions, torque converter slip can impose a
significant additional heat load on the cooling system.
Downshifting the transmission to the lowest possible
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STARTING AND OPERATING 69

gear (when climbing a grade), or shifting to NEUTRAL
(when stopped in heavy traffic) can help to reduce this
excess heat generation.
During cold temperatures, transmission operation may
be modified depending on engine and transmission
temperature as well as vehicle speed. This feature im-
proves warm up time of the engine and transmission to
achieve maximum efficiency. Engagement of the torque
converter clutch is inhibited until the transmission fluid
is warm (refer to the “Note” under “Torque Converter
Clutch” in this section). On cold starts below 41°F (5°C),
fifth and sixth gears may be inhibited briefly. During very
cold temperatures (-4°F [-20°C] or below), operation may
briefly be limited to third gear only. During this condi-
tion, the ability of the vehicle to accelerate under heavily
loaded conditions may be reduced. Normal operation
will resume once the transmission temperature has risen
to a suitable level.Transmission Limp Home Mode
Transmission function is monitored electronically for
abnormal conditions. If a condition is detected that could
result in transmission damage, Transmission Limp Home
Mode is activated. In this mode, the transmission remains
in third gear regardless of which forward gear is selected.
If the vehicle enters Limp Home Mode at highway
speeds, it will initially engage fifth gear, until the vehicle
slows to a speed where third gear can be engaged. PARK,
REVERSE, and NEUTRAL will continue to operate. Limp
Home Mode allows the vehicle to be driven to an
authorized dealer for service without damaging the
transmission.
In the event of a momentary problem, the transmission
can be reset to regain all forward gears by performing the
following steps:
1. Stop the vehicle.
70 STARTING AND OPERATING

WARNING!
Do not use the “TOW/HAUL” feature when driving
in icy or slippery conditions. The increased engine
braking can cause the rear wheels to slide, and the
vehicle to swing around with the possible loss of
vehicle control, which could cause an accident possi-
bly resulting in personal injury or death.
Torque Converter Clutch
A feature designed to improve fuel economy has been
included in the automatic transmission on your vehicle.
A clutch within the torque converter engages automati-
cally at calibrated speeds. This may result in a slightly
different feeling or response during normal operation in
the upper gears. When the vehicle speed drops or during
some accelerations, the clutch automatically disengages.NOTE:
•The torque converter clutch will not engage until the
transmission fluid and engine coolant are warm [usu-
ally after 1 to 3 miles (1.6 to 4.8 km) of driving].
Because the engine speed is higher when the torque
converter clutch is not engaged, it may seem as if the
transmission is not shifting into Overdrive when cold.
This is normal. Using the Electronic Range Select (ERS)
feature, when the transmission is sufficiently warm,
will demonstrate that the transmission is able to shift
into and out of Overdrive.
•If the vehicle has not been driven for several days, the
first few seconds of operation after shifting the trans-
mission into gear may seem sluggish. This is due to the
fluid partially draining from the torque converter into
the transmission. This condition is normal and will not
cause damage to the transmission. The torque con-
verter will refill within five seconds after starting the
engine.
74 STARTING AND OPERATING

MANUAL TRANSMISSION — IF EQUIPPED
WARNING!
You or others could be injured if you leave the
vehicle unattended without having the parking
brake fully applied. The parking brake should al-
ways be applied when the driver is not in the vehicle,
especially on an incline.
CAUTION!
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.
NOTE: During cold weather, you may experience in-
creased effort in shifting until the transmission fluid
warms up. This is normal.
Shifting
Truck models with manual transmission are equipped
with a clutch interlocking ignition system. The clutch
pedal must be fully pressed to start the vehicle.
Shift Pattern
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STARTING AND OPERATING 75

Fully press the clutch pedal before shifting gears. As you
release the clutch pedal, lightly press the accelerator
pedal.
This transmission has a “creeper” first gear which should
be used to start from a standing position when carrying
a payload or towing a trailer. Damage to the clutch can
result from starting in second or third gear with a loaded
vehicle. An unloaded vehicle may be launched in second
gear. Use each gear in numerical order – do not skip a
gear.
NOTE:When loaded, pulling a trailer or on a grade, the
truck should always start in first gear and not skip gears.
Recommended Vehicle Shift Speeds
To utilize your manual transmission efficiently for both
fuel economy and performance, it should be upshifted as
listed in recommended shift speed chart. Shift at the vehicle speeds listed for acceleration. When heavily
loaded or pulling a trailer these recommended up-shift
speeds may not apply.
Maximum Recommended Up-Shift Speeds
Gear
Selec- tion 1to2 2to3 3to4 4to5 5to6
Maxi- mum
Speed 7 mph
(11
km/h) 15 mph
(24
km/h) 25 mph
(40
km/h) 40 mph
(64
km/h) 45 mph
(72
km/h)
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.
76 STARTING AND OPERATING

WARNING!
Do not downshift for additional engine braking on a
slippery surface. The drive wheels could lose their
grip and the vehicle could skid.
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, and/or clutch disc
damage even if the clutch pedal is pressed.
Maximum Recommended Downshift Speeds
CAUTION!
Failure to follow the recommended downshifting
speeds may cause the engine to overspeed and/or
damage the clutch disc even if the clutch pedal is
pressed.
Maximum Recommended Downshifting Speeds
Gear
Selec- tion 6to5 5to4 4to3 3to2 2to1
Maxi- mum
Speed 68 mph
(109
km/h) 50 mph
(80
km/h) 32 mph
(51
km/h) 19 mph
(31
km/h) 10 mph
(16
km/h)
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STARTING AND OPERATING 77

Reverse Shifting
To shift into REVERSE (R), bring the vehicle to a com-
plete stop. Press the clutch and pause briefly to allow the
gear train to stop rotating. Beginning from the NEUTRAL
(N) position, move the shift lever in one quick smooth
motion straight across and into the REVERSE (R) area
(the driver will feel a firm “click” as the shifter passes the
“knock-over”). Complete the shift by pulling the shift
lever into REVERSE (R).
The “knock-over” prevents the driver from accidentally
entering the REVERSE (R) shift area and warns the driver
that they are about to shift the transmission into RE-
VERSE (R). Due to this feature, a slow shift to REVERSE
(R) can be perceived as a high shift effort.
To shift out of REVERSE bring the vehicle to a complete
stop and press the clutch. Shifting out of REVERSE prior
to a complete stop may cause high shift effort.
POWER TAKE OFF OPERATION — IF EQUIPPED
(CHASSIS CAB ONLY)
This vehicle when equipped with either the AS68RC
automatic six-speed or G-56 manual six-speed transmis-
sions, will allow for an aftermarket upfit with a transmis-
sion driven PTO (power take off). The customer will have
the ability to operate the PTO in either a “stationary” or
“mobile” mode. The vehicles will be factory set to the
“stationary” mode. In order to select the “mobile” mode
an authorized dealership is required to modify the vehi-
cle’s settings using their proprietary authorized dealer
service tool.
AS68RC Six-Speed Automatic Transmission Only
The PTO drive gear (part of the AS68RC) operates at
torque converter turbine speed. The turbine speed will be
less than engine speed when the torque converter clutch
is not engaged and will be same as engine speed when
the torque converter clutch is engaged.
78 STARTING AND OPERATING

Stationary Mode
To operate the PTO in this mode the vehicle must meet
the following conditions:
•Be in PARK position (vehicles equipped with auto-
matic transmission)
•Upfitter provider (on/off) switch has been activated
•Parking brake applied (vehicles equipped with
manual transmission)
•Brake pedal must not be applied
•Vehicle engine must be running
•No vehicle, brake or clutch switch faults present
•PTO must be correctly installed using the vehicle
provided circuits
The customer has the choice to operate the PTO by
utilizing the cruise control switches or by utilizing a remote control (provided by the PTO supplier). To oper-
ate the feature using the cruise control switches, the
customer must first activate the upfitter-provided on/off
switch which will turn on the PTO. In order to increase or
decrease the engine idle speed, to optimize the PTO
function, the “RESUME/ACCEL” and “DECEL” cruise
switches can be used respectively. To disengage PTO
operation and return to “standard vehicle operation”
simply turn the upfitter-provided on/off switch to the
OFF position.
The torque converter lockup clutch will automatically
engage at engine speeds above 1,200 RPM (engine speed)
in PTO stationary mode. Once engaged, the lockup clutch
will remain on and not disengage until the engine speed
is below 1,000 RPM. Lockup clutch engagement is desir-
able for certain types of PTO applications (AS68RC
Six-Speed Automatic Transmission Only).
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STARTING AND OPERATING 79