2023 RAM CHASSIS CAB towing

STARTING AND OPERATING129
DIESEL EXHAUST BRAKE (ENGINE
BRAKING)
The purpose of the exhaust brake (engine braking)
feature is to supply negative (braking) torque from
the engine. Typically, the engine braking is used
for, but not limited to, vehicle towing applications
where vehicle braking can be achieved by the
internal engine power, thereby sparing the
mechanical brakes of the vehicle.
Benefits of the exhaust brake are:
Vehicle driving control.
Reduced brake fade.
Longer brake life.
Faster cab warm-up.
The exhaust brake feature will only function when
the driver toggles it on by pushing the exhaust
brake button until the Exhaust Brake Indicator is
illuminated. Normal (Full Strength) exhaust brake
mode is indicated by a yellow Exhaust Brake
Indicator.
Exhaust Brake Switch

Once the Exhaust Brake Indicator is illuminated
and the vehicle is moving faster than 5 mph
(8 km/h); the exhaust brake will automatically
operate when the driver removes pressure from
the accelerator pedal. Exhaust braking is most
effective when the engine RPM is higher. The
automatic transmission will downshift more
aggressively in TOW/HAUL mode when the exhaust
brake is enabled to increase brake performance.
WARNING!
Never use the PARK position as a substitute
for the parking brake. Always apply the
parking brake fully when parked to guard
against vehicle movement and possible injury
or damage.
Never leave children alone in a vehicle, or with
access to an unlocked vehicle. Leaving unat -
tended children in a vehicle is dangerous for a
number of reasons. A child or others could be
seriously or fatally injured.
Do not leave the key fob in or near the vehicle,
or in a location accessible to children, and do
not leave a vehicle equipped with Keyless
Enter ‘n Go™ in the ACC or ON/RUN position.
A child could operate power windows, other
controls, or move the vehicle.
Be sure the parking brake is fully disengaged
before driving; failure to do so can lead to
brake failure and a collision.
Always fully apply the parking brake when
leaving your vehicle or it may roll and cause
damage or injury. Also, be certain to leave the
transmission in PARK. Failure to do so may
cause the vehicle to roll and cause damage or
injury.
CAUTION!
If the Brake System Warning Light remains on
with the parking brake released, a brake system
malfunction is indicated. Have the brake system
serviced by an authorized dealer immediately.
WARNING!
Do not use the exhaust brake feature when
driving in icy or slippery conditions as 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
may cause an accident possibly resulting in
personal injury or death.
4

23_DPF_OM_EN_USC_t.book Page 129

STARTING AND OPERATING133
The following indicators should be used to ensure
that you have properly engaged the transmission
into the PARK position:
Look at the transmission gear position display
and verify that it indicates the PARK position (P),
and is not blinking.
With the brake pedal released, verify that the
gear selector will not move out of PARK.
REVERSE (R)
This range is for moving the vehicle backward.
Shift into REVERSE only after the vehicle has come
to a complete stop.
NEUTRAL (N)
Use this range when the vehicle is standing for
prolonged periods with the engine running. Apply
the parking brake and shift the transmission into
PARK if you must exit the vehicle. DRIVE (D)
This range should be used for most city and
highway driving. It provides the smoothest upshifts
and downshifts, and the best fuel economy. The
transmission automatically upshifts through all
forward gears.
When frequent transmission shifting occurs (such
as when operating the vehicle under heavy loading
conditions, in hilly terrain, traveling into strong
head winds, or while towing a heavy trailer), select
TOW/HAUL mode or use the Electronic Range
Select (ERS) shift control to select a lower gear
range
Úpage 134. Under these conditions, using
a lower gear range will improve performance and extend transmission life by reducing excessive
shifting and heat build-up.
During extremely cold temperatures (-22°F
[-30°C] or below), transmission operation may be
modified depending on engine and transmission
temperature as well as vehicle speed. 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 may operate only in
certain gears, or may not shift at all. Vehicle
performance may be severely degraded and the
engine may stall. In some situations, the
transmission may not re-engage if the engine is
turned off and restarted. The Malfunction Indicator
Light (MIL) may be illuminated. A message in the
instrument cluster will inform the driver of the
more serious conditions, and indicate what actions
may be necessary.
In the event of a momentary problem, the
transmission can be reset to regain all forward
gears by performing the following steps:
NOTE:In cases where the instrument cluster message
indicates the transmission may not re-engage after
CAUTION!
DO NOT race the engine when shifting from
PARK or NEUTRAL into another gear range, as
this can damage the drivetrain.
Before moving the transmission gear selector
out of PARK, you must start the engine, and
also press the brake pedal. Otherwise,
damage to the gear selector could result.
WARNING!
Do not coast in NEUTRAL and never turn off the
ignition to coast down a hill. These are unsafe
practices that limit your response to changing
traffic or road conditions. You might lose control
of the vehicle and have a collision.
CAUTION!
Towing the vehicle, coasting, or driving for any
other reason with the transmission in NEUTRAL
can cause severe transmission damage.
For Towing A Disabled Vehicle Ú
page 339.
For Recreational Towing Ú page 195.4

23_DPF_OM_EN_USC_t.book Page 133

134STARTING AND OPERATING
engine shutdown, perform this procedure only in a
desired location (preferably, at an authorized
dealer).

1. Stop the vehicle.

2. Shift the transmission into PARK, if possible. If not, shift the transmission to NEUTRAL.
3. Push and hold the ignition switch until the engine turns off.
4. Wait approximately 30 seconds.
5. Restart the engine.
6. Shift into the desired gear range. If the problem is no longer detected, the
transmission will return to normal operation.
NOTE:Even if the transmission can be reset, we
recommend that you visit an authorized dealer at
your earliest possible convenience. An authorized
dealer has diagnostic equipment to assess the
condition of your transmission.
If the transmission cannot be reset, authorized
dealer service is required.
Electronic Range Select (ERS) Operation
The ERS shift control allows the driver to limit the
highest available gear when the transmission is in
DRIVE. For example, if you set the transmission
gear limit to FOURTH gear, the transmission will not shift above FOURTH gear (except to prevent
engine overspeed), but will shift through the lower
gears normally.
You can switch between DRIVE and ERS mode at
any vehicle speed. When the transmission gear
selector is in DRIVE, the transmission will operate
automatically, shifting between all available gears.
Tapping the GEAR “–” switch (on the steering
wheel) will activate ERS mode, display the current
gear in the instrument cluster, and set that gear as
the top available gear. Once in ERS mode, tapping
the GEAR “–” or GEAR “+” switch will change the
top available gear.

ERS Control
To exit ERS mode, simply push and hold the
GEAR “+” switch until the gear limit display
disappears from the instrument cluster.
When to Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying
a heavy load, etc., and frequent transmission
shifting occurs, push the TOW/HAUL switch to
activate TOW/HAUL mode. This will improve
performance and reduce the potential for
transmission overheating or failure due to
excessive shifting.

TOW/HAUL Switch

1 — GEAR “+” Switch
2 — GEAR “–” Switch
WARNING!
Do not downshift for additional engine braking
on a slippery surface. The drive wheels could
lose their grip and the vehicle could skid,
causing a collision or personal injury.

23_DPF_OM_EN_USC_t.book Page 134

136STARTING AND OPERATING
NOTE:On four-wheel drive vehicles be sure that the
transfer case is in a drive position.
When exiting the vehicle, always:
Apply the parking brake.
Shift the transmission into PARK.
Turn the engine off.
Remove the key fob.
The following indicators should be used to ensure
that you have properly engaged the transmission
into the PARK position:
When shifting into PARK, pull the gear selector
toward you and move it all the way counterclock-
wise until it stops.
Release the gear selector and make sure it is
fully seated in the PARK gate.
Look at the transmission gear position display
and verify that it indicates the PARK position (P).
With the brake pedal released, verify that the
gear selector will not move out of PARK.
REVERSE (R)
This range is for moving the vehicle backward.
Shift into REVERSE only after the vehicle has come
to a complete stop.
NEUTRAL (N)
Use this range when the vehicle is standing for
prolonged periods with the engine running. The
engine may be started in this range. Apply the
parking brake and shift the transmission into PARK
if you must exit the vehicle. DRIVE (D)
This range should be used for most city and
highway driving. It provides the smoothest upshifts
and downshifts, and the best fuel economy. The
transmission automatically upshifts through all
forward gears.
When frequent transmission shifting occurs (such
as when operating the vehicle under heavy loading
conditions, in hilly terrain, traveling into strong
head winds, or while towing a heavy trailer), select
TOW/HAUL mode or use the Electronic Range
Select (ERS) shift control to select a lower gear
range
Úpage 137. Under these conditions, using
a lower gear range will improve performance and
extend transmission life by reducing excessive
shifting and heat buildup.
CAUTION!
Before moving the transmission gear selector
out of PARK, you must turn the ignition to the
ON/RUN position, and also press the brake
pedal. Otherwise, damage to the gear selector
could result.
DO NOT race the engine when shifting from
PARK or NEUTRAL into another gear range, as
this can damage the drivetrain.WARNING!
Do not coast in NEUTRAL and never turn off the
ignition to coast down a hill. These are unsafe
practices that limit your response to changing
traffic or road conditions. You might lose control
of the vehicle and have a collision.
CAUTION!
Towing the vehicle, coasting, or driving for any
other reason with the transmission in NEUTRAL
can cause severe transmission damage.
For Towing A Disabled Vehicle Ú page 339.
For Recreational Towing Ú page 195.

23_DPF_OM_EN_USC_t.book Page 136

STARTING AND OPERATING137
If the transmission temperature exceeds normal
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 overheating.
If the transmission becomes extremely hot or is in
danger of overheating, the Transmission
Temperature Warning Light may illuminate and the
transmission may operate differently 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 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 improves 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 Ú page 139. On trucks with AS66RC or AS69RC transmission,
FIFTH and SIXTH gears may be inhibited briefly on
cold starts below 41°F (5°C), and during very cold
temperatures (-4°F [-20°C] or below), operation
may briefly be limited to third gear only. During this
condition, the ability of the vehicle to accelerate
under heavily loaded conditions may be reduced.
In all cases, 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 an
AS66RC/AS69RC equipped truck enters
Transmission 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. The Malfunction Indicator
Light (MIL) may be illuminated. Transmission 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.

2. Shift the transmission into PARK.
3. Turn the ignition to the OFF position.
4. Wait approximately 10 seconds.
5. Restart the engine.
6. Shift into the desired gear range. If the
problem is no longer detected, the
transmission will return to normal operation.
NOTE:Even if the transmission can be reset, we
recommend that you visit an authorized dealer at
your earliest possible convenience. An authorized
dealer has diagnostic equipment to assess the
condition of your transmission.
If the transmission cannot be reset, authorized
dealer service is required.
Electronic Range Select (ERS) Operation
The ERS shift control allows the driver to limit the
highest available gear when the transmission is in
DRIVE. For example, if you set the transmission
gear limit to FOURTH gear, the transmission will
not shift above FOURTH gear, but will shift through
the lower gears normally.
4

23_DPF_OM_EN_USC_t.book Page 137

138STARTING AND OPERATING
You can switch between DRIVE and ERS mode at
any vehicle speed. When the gear selector is in the
DRIVE position, the transmission will operate
automatically, shifting between all available gears.
Tapping the ERS “-” switch will activate ERS mode,
display the current gear in the instrument cluster,
and set that gear as the top available gear. Once in
ERS mode, tapping “-” or “+” will change the top
available gear.

Electronic Range Select

To exit ERS mode, simply push and hold the
ERS “+” switch until the gear limit display
disappears from the instrument cluster.
NOTE:To select the proper gear position for maximum
deceleration (engine braking), simply push and
hold the ERS “-” switch. The transmission will shift
to the range from which the vehicle can best be
slowed down.
Overdrive Operation

The automatic transmission includes an
electronically controlled Overdrive (FIFTH and SIXTH
gears). The transmission will automatically shift into
Overdrive if the following conditions are present:

The gear selector is in the DRIVE position.
The transmission fluid has reached an
adequate temperature.
The engine coolant has reached an adequate
temperature.
Vehicle speed is sufficiently high.
The TOW/HAUL switch has not been activated.
The driver is not heavily pressing the acceler -
ator.
When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying
a heavy load, etc., and frequent transmission
shifting occurs, push the TOW/HAUL switch to
activate TOW/HAUL mode. This will improve
performance and reduce the potential for
transmission overheating or failure due to
excessive shifting. When operating in TOW/HAUL
mode, transmission upshifts are delayed, and the
transmission will automatically downshift (for
engine braking) when the throttle is closed and/or
during steady braking maneuvers.

TOW/HAUL Switch

1 — GEAR “+” Switch
2 — GEAR “–” Switch
WARNING!
Do not downshift for additional engine braking
on a slippery surface. The drive wheels could
lose their grip and the vehicle could skid,
causing a collision or personal injury.
CAUTION!
When using ERS for engine braking while
descending steep grades, be careful not to
overspeed the engine. Apply the brakes as
needed to prevent engine overspeed.

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140STARTING AND OPERATING
FOUR-WHEEL DRIVE OPERATION —
IF EQUIPPED
Four-wheel drive trucks are equipped with either a
manually shifted transfer case or an electronically
shifted transfer case.
ELECTRONICALLY SHIFTED TRANSFER
C
ASE (8-SPEED TRANSMISSION) — IF
E
QUIPPED
This is an electronically shifted transfer case and is
operated by the 4WD Control Switch (Transfer
Case Switch), which is located on the instrument
panel.

Four-Position Transfer Case
This electronically shifted transfer case provides
four positions:
Two-Wheel Drive High Range (2WD)
Four-Wheel Drive High Range (4WD HIGH)
Four-Wheel Drive Low Range (4WD LOW)
N (Neutral)
For additional information on the appropriate use
of each transfer case position, see the information
below:
2WD
Two-Wheel Drive High Range — This range is for
normal street and highway driving on dry, hard
surfaced roads.
4WD HIGH

Four-Wheel Drive High Range — This range provides
torque to the front driveshaft (engages four-wheel
drive) which allows front and rear wheels to spin at
the same speed. This provides additional traction for
loose, slippery road surfaces only.

4WD LOW
Four-Wheel Drive Low Range — This range provides
low speed four-wheel drive. It maximizes torque
(increased torque over 4WD High) to the front
wheels, allowing front and rear wheels to rotate at
the same speed. This range provides additional
traction and maximum pulling power for loose,
slippery road surfaces only. Do not exceed 25 mph
(40 km/h) in this range. N (Neutral)
N (Neutral) — This range disengages both the front
and rear driveshafts from the powertrain. To be
used for flat towing behind another vehicle
Ú
page 194.WARNING!
You or others could be injured or killed if you
leave the vehicle unattended with the transfer
case in the N (Neutral) position without first
fully engaging the parking brake. The transfer
case N (Neutral) position disengages both the
front and rear drive shaft from the powertrain,
and will allow the vehicle to roll, even if the
transmission is in PARK. The parking brake
should always be applied when the driver is
not in the vehicle.
The transmission may not engage PARK if the
vehicle is moving. Always bring the vehicle to a
complete stop before shifting to PARK, and
verify that the transmission gear position indi -
cator solidly indicates PARK (P) without
blinking. Ensure that the vehicle is completely
stopped, and the PARK position is properly
indicated, before exiting the vehicle.

23_DPF_OM_EN_USC_t.book Page 140

STARTING AND OPERATING141
This electronically shifted transfer case is designed
to be driven in the two-wheel drive position (2WD)
for normal street and highway conditions on dry
hard surfaced roads. Driving the vehicle in
two-wheel drive will have greater fuel economy
benefits as the front axle is not engaged in
two-wheel drive.
When additional traction is required, the transfer
case 4WD HIGH and 4WD LOW positions can be
used to maximize torque to the front driveshaft,
forcing the front and rear wheels to rotate at the
same speed. This is accomplished by pushing the
desired position on the four-wheel drive control
switch.
For specific shifting instructions Ú page 144.
The 4WD HIGH and 4WD LOW positions are
designed for loose, slippery road surfaces only.
Driving in the 4WD HIGH and 4WD LOW positions
on dry, hard surfaced roads may cause increased
tire wear and damage to the driveline components.
NOTE:The transfer case N (Neutral) button is located in
the center of the four-wheel drive Control Switch
and is pushed by using a ballpoint pen or similar
object. The transfer case N (Neutral) position is to
be used for recreational towing only Ú page 194.Transfer Case Position Indicator Lights
The Transfer Case Position Indicator Lights (4WD
and 4WD LOW) are located in the instrument
cluster and indicate the current and desired
transfer case selection. When you select a
different transfer case position, the indicator lights
will do the following:
If All Of The Following Shift Conditions Are Met:


1. The current position indicator light will turn off.

2. The selected position indicator light will flash until the transfer case completes the shift.
3. When the shift is complete, the indicator light for the selected position will stop flashing and
remain on.
If One Or More Of The Following Shift Conditions
Are Not Met:

1. The indicator light for the current position will remain on.

2. The newly selected position indicator light will continue to flash.
3. The transfer case will not shift.
NOTE:Before retrying a selection, make certain that all
the necessary requirements for selecting a new
transfer case position have been met. To retry the selection, push the current position, wait five
seconds, and retry selection Ú
page 144.
The SERV 4WD Warning Light monitors the
electronically shifted four-wheel drive system. If
this light remains on after engine start-up or
illuminates during driving, it means that the
four-wheel drive system is not functioning properly
and that service is required.
NOTE:Do not attempt to make a shift while only the front
or rear wheels are spinning. This could cause
damage to driveline components.
When operating your vehicle in 4WD LOW, the
engine speed is approximately three times that of
the two-wheel drive or 4WD HIGH 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 four-wheel drive vehicles
depends on tires of equal size, type and
circumference on each wheel. Any difference in
tire size can cause damage to the drivetrain.
WARNING!
Always engage the parking brake when powering
down the vehicle if the SERV 4WD Warning Light
is illuminated. Not engaging the parking brake
may allow the vehicle to roll which may cause
personal injury or death.4

23_DPF_OM_EN_USC_t.book Page 141