brake RAM CHASSIS CAB 2021 Workshop Manual

STARTING AND OPERATING149
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 150. 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 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 addi
-
tional heat load on the cooling system. Down -
shifting 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 151.
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 350.
For Recreational Towing Ú page 215.
4

21_DPF_OM_EN_USC_t.book Page 149

STARTING AND OPERATING151

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 accelerator.

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 automatically 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 (usually after 1 to 3 miles
(2 to 5 km) of driving). Because engine speed
is higher when the torque converter clutch is
not engaged, it may seem as if the transmis
-
sion is not shifting properly when cold; This is
normal. Using the Electronic Range Select
(ERS) shift control, when the transmission is
sufficiently warm, will demonstrate that the
transmission is able to shift into and out of
Overdrive.
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.4

21_DPF_OM_EN_USC_t.book Page 151

STARTING AND OPERATING153
(Continued)
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 (EIGHT SPEED TRANSMISSION) —
I
F EQUIPPED
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 mode 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 mode 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 driveshaft, 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 214.
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.

4

21_DPF_OM_EN_USC_t.book Page 153

STARTING AND OPERATING155
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.
Because four-wheel drive provides improved
traction, there is a tendency to exceed safe
turning and stopping speeds. Do not go faster
than road conditions permit.
Shifting Procedure
NOTE:
If any of the requirements to select a new
transfer case position have not been met,
the transfer case will not shift. The position
indicator light for the previous position will
remain on and the newly selected position
indicator light will continue to flash until all
the requirements for the selected position
have been met.
If all the requirements to select a new
transfer case position have been met, the
current position indicator light will turn off,
the selected position indicator light will flash
until the transfer case completes the shift.
When the shift is complete, the position indi -
cator light for the selected position will stop
flashing and remain on. 2WD To 4WD HIGH

Push the desired position on the four-wheel drive
control switch to shift the transfer case. Shifts
between two-wheel drive and 4WD High can
be done with the vehicle stopped or in motion.
With the vehicle in motion, the transfer case will
engage/disengage faster if you momentarily
release the accelerator pedal after turning the
control switch. If the vehicle is stopped, the
ignition switch must be in the ON position with
the engine either running or off. This shift cannot
be completed if the ignition switch is in the ACC
position.

NOTE:
The four-wheel drive system will not allow shifts
between 2WD/4WD High if the front and/or
rear wheels are spinning (no traction). In this
situation, the selected position indicator light
will flash and the original position indicator light
will remain on. At this time, reduce speed and
stop spinning the wheels to complete the shift.
WARNING!
Always engage the parking brake when
powering down the vehicle if the “SVC 4WD
Warning Light” is illuminated. Not engaging
the parking brake may allow the vehicle to roll
which may cause personal injury or death.
4

21_DPF_OM_EN_USC_t.book Page 155

STARTING AND OPERATING157
For additional information on the appropriate
use of each transfer case mode 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
maximizes torque to the front driveshaft, forcing
the front and rear wheels to rotate at the same
speed. This range 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 to the front driveshaft,
forcing the 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). 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 214.
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. 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 rotating the four-wheel drive Control Switch
to the desired position.
For specific shifting instructions Ú
page 159.

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 NEUTRAL button is located on
the lower left hand corner of the four-wheel drive
Control Switch. The transfer case NEUTRAL posi -
tion is to be used for recreational towing only

Ú
page 214.

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 shafts 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.

4

21_DPF_OM_EN_USC_t.book Page 157

158STARTING AND OPERATING
Transfer Case Position Indicator Lights
The Transfer Case Position Indicator Lights
(four-wheel drive 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, turn the control switch back to the
current position, wait five seconds, and retry
selection Ú
page 159.
The “SVC 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, as this can
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.
Because four-wheel drive provides improved
traction, there is a tendency to exceed safe
turning and stopping speeds. Do not go faster
than road conditions permit.
WARNING!
Always engage the parking brake when
powering down the vehicle if the “SVC 4WD
Warning Light” is illuminated. Not engaging
the parking brake may allow the vehicle to
roll, which may cause personal injury.

21_DPF_OM_EN_USC_t.book Page 158

STARTING AND OPERATING161
The 4H and 4L positions are intended for loose,
slippery road surfaces only. Driving in the 4H
and 4L positions on dry, hard surfaced roads
may cause increased tire wear and damage to
the driveline components.
The “Transfer Case Position Indicator Light” in
the instrument cluster will alert the driver that
the vehicle is in four-wheel drive and that the
front and rear driveshafts are locked together.
This light will illuminate when the transfer case
is shifted into either the 4H or 4L position. There
is no light for the 2H or N (Neutral) positions on
some models.
When operating your vehicle in 4L, the engine
speed is approximately three times that of the
4H or 4L 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
will adversely affect shifting and can cause
damage to the drivetrain. NOTE:
Do not attempt to make a shift while only the
front or rear wheels are spinning, as this can
cause damage to driveline components.
Because four-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 temperatures.Shifting Procedure — Manually Shifted
Transfer Case
2H To 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/disengage faster if
you momentarily release the accelerator pedal
after completing the shift. Apply a constant
force when shifting the transfer case lever.
2WD High Or 4WD High To 4WD Low
NOTE:
When shifting into or out of 4L some gear noise
may be heard. This noise is normal and is not
detrimental to the vehicle or occupants.
With the vehicle rolling at 2 to 3 mph (3 to
5 km/h), shift the transmission into NEUTRAL.
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 Neutral.
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 shafts 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.

4

21_DPF_OM_EN_USC_t.book Page 161

162STARTING AND OPERATING
NOTE:
Pausing in transfer case N (Neutral) in vehi -
cles equipped with an automatic transmis -
sion may require shutting the engine OFF to
avoid gear clash while completing the shift. If
difficulty occurs, shift the transmission into
Neutral, hold your foot on the brake, and turn
the engine OFF. Complete the range shift to
the desired mode.

Shifting into or out of 4L is possible with the
vehicle completely stopped, however difficulty
may occur 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 preferred
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).

Do not attempt to shift into or out of 4L while
the transmission is in gear.
Transfer Case Position Indicator Light
The “Transfer Case Position Indicator Light” in
the instrument cluster is used to alert the driver
that the front axle is fully engaged and all four
wheels are driving.
LIMITED-SLIP DIFFERENTIAL
The limited-slip differential provides additional
traction on snow, ice, mud, sand and gravel,
particularly when there is a difference between
the traction characteristics of the surface under
the right and left rear wheels. During normal
driving and cornering, the limited-slip unit
performs similarly to a conventional differential.
On slippery surfaces, however, the differential
delivers more of the driving effort to the rear
wheel having the better traction.

The limited-slip differential is especially helpful
during slippery driving conditions. With both rear
wheels on a slippery surface, a slight application
of the accelerator will supply maximum traction.
When starting with only one rear wheel on an
excessively slippery surface, slight momentary
application of the parking brake may be
necessary to gain maximum traction.
Care should be taken to avoid sudden
accelerations when both rear wheels are on a
slippery surface. This could cause both rear
wheels to spin, and allow the vehicle to slide
sideways on the crowned surface of a road or in
a turn.
WARNING!
On vehicles equipped with a limited-slip
differential never run the engine with one rear
wheel off the ground since the vehicle may
drive through the rear wheel remaining on the
ground. You could lose control of the vehicle.

21_DPF_OM_EN_USC_t.book Page 162

STARTING AND OPERATING165
To Set A Desired Speed
Turn the Cruise Control on. When the vehicle
has reached the desired speed, push the SET (-)
button and release. Release the accelerator
and the vehicle will operate at the selected
speed. Once a speed has been set, a message
“CRUISE CONTROL SET TO MPH (km/h)” will
appear indicating the set speed. A cruise
indicator lamp, along with set speed will also
appear and stay on in the instrument cluster
display when the speed is set.
NOTE:
The vehicle should be traveling at a steady
speed and on level ground before pushing the
SET (-) button.
To Vary The Speed Setting
To Increase Or Decrease The Set Speed
When Cruise Control is set, you can increase
the speed by pushing the RES (+) button, or
decrease speed by pushing the SET (-) button.
U.S. Speed (mph)
Pushing the RES (+) button, or SET (-) button
once will result in a 1 mph speed adjustment.
Each subsequent tap of the button results in
an adjustment of 1 mph.
If the button is continually pushed, the set
speed will continue to adjust until the button
is released, then the new set speed will be
established.
Metric Speed (km/h)
Pushing the RES (+), or SET (-) button once
will result in a 1 km/h speed adjustment.
Each subsequent tap of the button results in
an adjustment of 1 km/h.
If the button is continually pushed, the set
speed will continue to adjust until the button
is released, then the new set speed will be
established.
To Accelerate For Passing
While the Cruise Controls is set, press the
accelerator as you would normally. When the
pedal is released, the vehicle will return to the
set speed.
Using Cruise Control On Hills
The transmission may downshift on hills to
maintain the vehicle set speed.
The Cruise Control system maintains speed up
and down hills. A slight speed change on
moderate hills is normal. On steep hills, a greater speed loss or gain may occur so it may
be preferable to drive without Cruise Control.
To Resume Speed
To resume a previously set speed, push the
RES (+) button and release. Resume can be
used at any speed above 20 mph (32 km/h).
To Deactivate
A soft tap on the brake pedal, pushing the
CANCEL button, or normal brake pressure while
slowing the vehicle will deactivate the Cruise
Control without erasing the set speed from
memory.
WARNING!
Cruise Control can be dangerous where the
system cannot maintain a constant speed.
Your vehicle could go too fast for the
conditions, and you could lose control and
have an accident. Do not use Cruise Control
in heavy traffic or on roads that are winding,
icy, snow-covered or slippery.
4

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166STARTING AND OPERATING
(Continued)
The following conditions will also deactivate the
Cruise Control without erasing the set speed
from memory:
Vehicle parking brake is applied
Stability event occurs
Gear selector is moved out of DRIVE
Engine overspeed occurs
Pushing the on/off button, or placing the
ignition in the OFF position, erases the set
speed from memory.
ADAPTIVE CRUISE CONTROL (ACC) — IF
E
QUIPPED

Adaptive Cruise Control (ACC) increases the
driving convenience provided by Cruise Control
while traveling on highways and major roadways.
However, it is not a safety system and not
designed to prevent collisions. The Cruise Control
function performs differently if your vehicle is not
equipped with ACC
Ú
page 164.
ACC will allow you to keep Cruise Control
engaged in light to moderate traffic conditions
without the constant need to reset your speed.
ACC utilizes a radar sensor and a forward facing
camera designed to detect a vehicle directly
ahead of you to maintain a set speed.
NOTE:
If the ACC sensor detects a vehicle ahead,
ACC will apply limited braking or acceleration
(not to exceed the original set speed) auto
-
matically to maintain a preset following
distance, while matching the speed of the
vehicle ahead.
Any chassis/suspension or tire size modifica -
tions to the vehicle will affect the perfor -
mance of the Adaptive Cruise Control and
Forward Collision Warning system.
Fixed Speed Cruise Control alone (an ACC
distance not set) will not detect vehicles
directly ahead of you. Always be aware of the
mode selected.
WARNING!

Adaptive Cruise Control (ACC) is a conve -
nience system. It is not a substitute for active
driver involvement. It is always the driver’s
responsibility to be attentive of road, traffic,
and weather conditions, vehicle speed,
distance to the vehicle ahead; and, most
importantly, brake operation to ensure safe
operation of the vehicle under all road condi -
tions. Your complete attention is always
required while driving to maintain safe
control of your vehicle. Failure to follow these
warnings can result in a collision and death
or serious personal injury.

The ACC system:
Does not react to pedestrians,
oncoming vehicles, and stationary
objects (e.g., a stopped vehicle in a
traffic jam or a disabled vehicle).
Cannot take street, traffic, and weather
conditions into account, and may be
limited upon adverse sight distance
conditions.

21_DPF_OM_EN_USC_t.book Page 166