brake RAM CHASSIS CAB 2020 Repair Manual

STARTING AND OPERATING219
Electronically Shifted Transfer Case (Eight
Speed Transmission) — If Equipped
This is an electronic shift transfer case and is
operated by the 4WD Control Switch (Transfer
Case Switch), which is located on the instru -
ment 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 maxi
-
mizes 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. Refer to “Recreational Towing” in this
section for further information.
WARNING!
You or others could be injured or killed if
you leave the vehicle unattended with the
transfer case in the NEUTRAL (N) position
without first fully engaging the parking
brake. The transfer case NEUTRAL (N) posi
-
tion disengages both the front and rear
drive shaft from the powertrain, and will
allow the vehicle to roll, even if the trans -
mission 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 indicator solidly indicates PARK (P)
without blinking. Ensure that the vehicle is
completely stopped, and the PARK position
is properly indicated, before exiting the
vehicle.
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STARTING AND OPERATING221
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 2WD 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 circum -
ference 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 indi -
cator 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 4WD control
switch to shift the transfercase. Shifts between
2WD and 4WD HIGH can be done with the
vehicle stopped or in motion. With the vehicle in
motion, the transfer case will engage/disen
-
gage 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.
5

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STARTING AND OPERATING223
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 maxi -
mizes 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. Refer to “Recreational Towing” in this
section for further information.
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 posi
-
tions 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 4WD Control
Switch to the desired position.
Refer to “Shifting Procedure” in this section for
specific shifting instructions.
The 4WD HIGH and 4WD LOW positions are
designed for loose, slippery road surfaces only.
Driving in the 4WD HIGH and 4WD LOW posi
-
tions 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 4WD Control
Switch. The transfer case NEUTRAL position is
to be used for recreational towing only. Refer to
“Recreational Towing” in “Starting And Oper -
ating” for further information.
Transfer Case Position Indicator Lights
The Transfer Case Position Indicator Lights
(4WD and 4WD LOW) are located in the instru -
ment 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:
WARNING!
You or others could be injured or killed if you
leave the vehicle unattended with the transfer
case in the NEUTRAL position without first
fully engaging the parking brake. The transfer
case 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.
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224STARTING AND OPERATING
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. To find the shift requirements, refer
to the "Shifting Procedure" for your transfer
case, located in this section.
The “SVC 4WD Warning Light” monitors the
electronic shift four-wheel drive system. If this
light remains on after engine start up or illumi
-
nates during driving, it means that the
four-wheel drive system is not functioning prop -
erly 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 2WD 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 circum
-
ference 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 indi -
cator 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. To retry a shift: return the
control switch back to the original position,
make certain all shift requirements have
been met, wait five seconds and try the shift
again.
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.

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STARTING AND OPERATING227
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.
Two-Wheel Drive High Range (2H)
Two-Wheel Drive High Range — This range is for
normal street and highway driving on dry hard
surfaced roads.
Four-Wheel Drive High Range (4H)
Four-Wheel Drive High Range — This range locks
the front and rear driveshafts together forcing
the front and rear wheels to rotate at the same
speed. Additional traction for loose, slippery
road surfaces only.
N (Neutral)
Neutral — This range disengages the front and
rear driveshafts from the powertrain. To be
used for flat towing behind another vehicle.
Refer to “Recreational Towing” in “Starting And
Operating” for further information.
Four-Wheel Drive Low Range (4L)
Four-Wheel Drive Low Range — This range locks
the front and rear driveshafts together forcing
the front and rear wheels to rotate at the same
speed. Additional traction and maximum pulling
power for loose, slippery road surfaces only. Do
not exceed 25 mph (40 km/h).
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.
2H Or 4H To 4L
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 NEUTRAL position without first
fully engaging the parking brake. The transfer
case 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.
CAUTION!
Do not use 4L (Low) range when operating
the vehicle on dry pavement. Driveline
hardware damage can result.
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228STARTING AND OPERATING
NOTE:
Pausing in transfer case Neutral in vehicles
equipped with an automatic transmission
may require shutting the engine OFF to avoid
gear clash while completing the shift. If diffi -
culty 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 diffi -
culty 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 appli -
cation 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 accelera-
tions 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.
POWER TAKE OFF (PTO) OPERATION — IF
EQUIPPED
This vehicle when equipped with PTO Prep and
the AS66RC/AS69RC automatic six-speed, 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”, “mobile” or “remote” mode. The
vehicles will be factory set to the “stationary”
mode. To select a different mode, or to change
any other PTO setting, you will need to enter the
commercial vehicle menu on the instrument
cluster screen. Details of the PTO selection
modes and further PTO information is available
at the Ram Truck Bodybuilders web site: https:/
/www.ramtrucks.com/ram-commerical/
body-builders-guide.html
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.

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STARTING AND OPERATING231
Metric Speed (km/h)
Pushing the RES (+) button once will result in
a 1 km/h increase in set speed. Each subse -
quent tap of the button results in an increase
of 1 km/h.
If the button is continually pushed, the set
speed will continue to increase until the
button is released, then the new set speed
will be established.
To Decrease Speed
When the Speed Control is set, you can
decrease speed by pushing the SET (-) button.
The driver’s preferred units can be selected
through the instrument panel settings (if
equipped). Refer to “Getting To Know Your
Instrument Panel” for more information. The
speed decrement shown is dependent on the
chosen speed unit of U.S. (mph) or Metric
(km/h):
U.S. Speed (mph)
Pushing the SET (-) button once will result in
a 1 mph decrease in set speed. Each subse -
quent tap of the button results in a decrease
of 1 mph.
If the button is continually pushed, the set
speed will continue to decrease until the
button is released, then the new set speed
will be established.
Metric Speed (km/h)
Pushing the SET (-) button once will result in
a 1 km/h decrease in set speed. Each subse -
quent tap of the button results in a decrease
of 1 km/h.
If the button is continually pushed, the set
speed will continue to decrease until the
button is released, then the new set speed
will be established.
To Accelerate For Passing
Press the accelerator as you would normally.
When the pedal is released, the vehicle will
return to the set speed.
Using Speed Control On Hills
The transmission may downshift on hills to
maintain the vehicle set speed.
NOTE:
The Speed 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
Speed 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 Speed
Control without erasing the set speed from
memory.
Pushing the on/off button, or placing the igni
-
tion in the OFF position, erases the set speed
from memory.
WARNING!
Speed 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 Speed Control
in heavy traffic or on roads that are winding,
icy, snow-covered or slippery.
5

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232STARTING AND OPERATING
(Continued)
ADAPTIVE CRUISE CONTROL (ACC) — IF
EQUIPPED
Adaptive Cruise Control (ACC) increases the
driving convenience provided by cruise control
while traveling on highways and major road-
ways. However, it is not a safety system and not
designed to prevent collisions. Speed Control
function performs differently. Please refer to
the proper section within this chapter.
ACC will allow you to keep cruise control
engaged in light to moderate traffic conditions
without the constant need to reset your cruise
control. ACC utilizes a radar sensor and a
forward facing camera designed to detect a
vehicle directly ahead of you.
NOTE:
If the sensor does not detect a vehicle ahead
of you, ACC will maintain a fixed set speed.
If the ACC sensor detects a vehicle ahead,
ACC will apply limited braking or accelerate
(not to exceed the original set speed) auto -
matically to maintain a preset following
distance, while matching the speed of the
vehicle ahead. The Cruise Control system has two control
modes:
Adaptive Cruise Control mode for main
-
taining an appropriate distance between
vehicles.
Normal (Fixed Speed) Cruise Control mode
for cruising at a constant preset speed. For
additional information, refer to “Normal
(Fixed Speed) Cruise Control Mode” in this
section.
NOTE:
Normal (Fixed Speed) Cruise Control will not
react to preceding vehicles. Always be aware of
the mode selected.
You can change the mode by using the Cruise
Control buttons. The two control modes func -
tion differently. Always confirm which mode is
selected.
WARNING!
Adaptive Cruise Control (ACC) is a conve -
nience system. It is not a substitute for
active driving 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 opera -
tion to ensure safe operation of the vehicle
under all road conditions. 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.

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STARTING AND OPERATING233
(Continued)
Adaptive Cruise Control (ACC) Operation
The speed control buttons (located on the right
side of the steering wheel) operate the ACC
system.
Adaptive Cruise Control Buttons

NOTE:
Any chassis/suspension or tire size modifica -
tions to the vehicle will affect the performance
of the Adaptive Cruise Control and Forward
Collision Warning System.
Does not always fully recognize complex driving conditions, which can
result in wrong or missing distance
warnings.
Will bring the vehicle to a complete stop while following a target vehicle and hold
the vehicle for approximately two
seconds in the stop position. At this
point, there will be an “ACC may cancel
soon” chime and warning to the driver.
When ACC is cancelled, the system will
release the brakes and the driver must
take over braking. The system can be
resumed when the target vehicle drives
off by releasing the brake and pushing
the resume button on the steering
wheel.
WARNING! (Continued)
You should switch off the ACC system:
When driving in fog, heavy rain, heavy
snow, sleet, heavy traffic, and complex
driving situations (i.e., in highway construc -
tion zones).
When entering a turn lane or highway off
ramp; when driving on roads that are
winding, icy, snow-covered, slippery, or
have steep uphill or downhill slopes.
When towing a trailer up or down steep
slopes.
When circumstances do not allow safe
driving at a constant speed.
WARNING! (Continued)
1 — Adaptive Cruise Control On/Off Button
2 — Distance Button
3 — RES (+)
4 — SET (-)
5 — CANCEL
6 — Normal (Fixed Speed) Cruise Control On/Off
Button
5

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234STARTING AND OPERATING
Activating Adaptive Cruise Control (ACC)
You can only engage ACC if the vehicle speed is
above 0 mph (0 km/h).
The minimum set speed for the ACC system is
20 mph (32 km/h).
When the system is turned on and in the ready
state, the instrument cluster display will read
“ACC Ready.”
When the system is off, the instrument cluster
display will read “Adaptive Cruise Control (ACC)
Off.”
NOTE:
You cannot engage ACC under the following
conditions:
When in Four-Wheel Drive Low.
When you apply the brakes.
When the parking brake is applied.
When the automatic transmission is in PARK,
REVERSE or NEUTRAL.
When the vehicle speed is outside of the
speed range.
When the brakes are overheated.
When the driver door is open at low speed.
When the driver seat belt is unbuckled at low
speed.
Electronic Stability Control (ESC) Full Off
mode is active.
To Activate/Deactivate
Push and release the Adaptive Cruise Control
(ACC) on/off button. The ACC menu in the
instrument cluster displays “ACC Ready.”

Adaptive Cruise Control Ready
To turn the system off, push and release the
Adaptive Cruise Control (ACC) on/off button
again. At this time, the system will turn off and
the instrument cluster display will show “Adap
-
tive Cruise Control (ACC) Off.”

Adaptive Cruise Control Off

WARNING!
Leaving the Adaptive Cruise Control (ACC)
system on when not in use is dangerous. You
could accidentally set the system or cause it
to go faster than you want. You could lose
control and have a collision. Always leave the
system off when you are not using it.

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