brake RAM CHASSIS CAB 2019 Repair Manual

STARTING AND OPERATING 279
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, exces -
sive vehicle loading, or cold temperatures.
Two-Wheel Drive High Range (2H)
Rear-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.
Neutral (N)
Neutral — This range disengages the front and rear drivesh -
afts 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).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. 5

280 STARTING AND OPERATING
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. 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 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 transmis -
sion is in gear.
Transfer Case Position Indicator Light
The “Transfer Case Position Indicator Light” in the instru -
ment cluster is used to alert the driver that the front axle is
fully engaged and all four wheels are driving.

STARTING AND OPERATING 281
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 simi -
larly 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 slip -
pery 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 appli -
cation 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 side -
ways on the crowned surface of a road or in a turn.
POWER TAKE OFF OPERATION — IF EQUIPPED
(CHASSIS CAB ONLY)
This vehicle when equipped with PTO Prep and the AS66RC
automatic six-speed, will allow for an aftermarket upfit with
a transmission 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. To select “mobile” mode, you
will need to enter the commercial vehicle menu on the instru -
ment cluster screen and select mobile PTO mode. Details of
the PTO selection modes and further PTO information is
available at the Ram Truck Bodybuilders web site:
www.rambodybuilder.com .
AS66RC Six-Speed Automatic Transmission Only
The PTO drive gear (part of the AS66RC) 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.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. 5

282 STARTING AND OPERATING
Stationary Mode
To operate the PTO in this mode the vehicle must meet the
following conditions:
• Transmission in PARK position.
• PTO switch has been activated.
• Brake pedal must not be applied.
• Vehicle engine must be running.
• No vehicle, or brake faults present.
• PTO must be correctly installed using the vehicle provided
circuits.
The instrument cluster will display a "PTO On" message for
five seconds if the above conditions are met. Otherwise, the
instrument cluster will display a message "To Operate PTO
Shift To Park" indicating what operator action should be
taken to engage the PTO mode.
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 operate the feature using
the cruise control switches, the customer must first activate
the PTO 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 opera -
tion and return to “standard vehicle operation” simply
toggle the PTO switch to the OFF position.
The torque converter clutch (TCC) will automatically engage
at engine speeds above 1,200 RPM (engine speed) in PTO
stationary mode. Once engaged, the TCC will remain
applied and will not disengage until the engine speed falls
below 1,000 RPM. TCC engagement is desirable for certain
types of PTO applications (Automatic Transmission Only).
To operate the PTO via a remote switch, the customer must
make sure the above conditions are met. It is vital for proper
operation that the PTO and remote have been installed
correctly, paying special attention to ensure the vehicle
provided wiring has been connected properly. This is the
responsibility of the installer of the PTO and switches/
remote system. It is the responsibility of the PTO manufac -
turer to ensure that their electrical (switches and remote)
system is compatible with the vehicle’s electrical architecture
and software functionality.
NOTE:
Single set speed can be programmed via the PTO menu on
the instrument cluster display. Further details are available
at the Ram Truck Bodybuilders web site located at rambody -
builder.com

STARTING AND OPERATING 283
Mobile Mode
To operate the PTO in this mode the vehicle must meet the
following conditions:
• Mobile mode is activated via the menu on the instrument
cluster display.
• (ON/OFF) switch has been activated.
• Transmission must be in PARK or DRIVE.
• Parking brake must not be applied.
• Brake pedal must not be applied.
• No vehicle or brake faults present.
• Vehicle engine must be running.
• PTO must be correctly installed using the vehicle provided
circuits.
The customer may choose to use the PTO while the vehicle is
moving. To do so, the PTO function must be activated prior
to taking the vehicle out of PARK. This is accomplished by
activating the upfitter-provided PTO on/off switch. At this
point, the customer may place the vehicle in a forward or
reverse gear and have PTO operation once the vehicle begins
to move. To disengage PTO operation and return to “stan -
dard vehicle operation” simply toggle the on/off switch to
the OFF position. NOTE:
For application specific information with respect to PTO and
pump requirements and additional vehicle information
(wiring schematics, preset idle values, engine speed limits,
and vehicle hardware and software requirements) please
refer to the Body Builders Guide by accessing rambody -
builder.com and choosing the appropriate links.
POWER STEERING
Hydraulic Power Steering
The standard power steering system will give you good
vehicle response and increased ease of maneuverability in
tight spaces. The system will provide mechanical steering
capability if power assist is lost.
If for some reason the power assist is interrupted, it will still
be possible to steer your vehicle. Under these conditions, you
will observe a substantial increase in steering effort, espe -
cially at very low vehicle speeds and during parking maneu -
vers. 5

288 STARTING AND OPERATING
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 returning the ignition to OFF,
erases the set speed from memory.
ADAPTIVE CRUISE CONTROL (ACC) — IF EQUIPPED
Adaptive Cruise Control (ACC) increases the driving conve -
nience provided by cruise control while traveling on high -
ways and major roadways. However, it is not a safety system
and not designed to prevent collisions. Speed Control func -
tion 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) automatically 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 maintaining an appro -
priate 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 function differently. Always
confirm which mode is selected.

STARTING AND OPERATING 289
(Continued)WARNING!
• Adaptive Cruise Control (ACC) is a convenience
system. It is not a substitute for active driving involve -
ment. It is always the driver’s responsibility to be atten -
tive of road, traffic, and weather conditions, vehicle
speed, distance to the vehicle ahead; and, most impor -
tantly, brake operation to ensure safe operation of the
vehicle under all road conditions. Your complete atten -
tion is always required while driving to maintain safe
control of your vehicle. Failure to follow these warn -
ings 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.
• 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.
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 construction 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)
5

290 STARTING AND OPERATING
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 modifications to the
vehicle will effect the performance of the Adaptive Cruise
Control and Forward Collision Warning System. 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.1 — Adaptive Cruise Control On/Off Button
2 — Distance Button

292 STARTING AND OPERATING
To Set A Desired ACC Speed
When the vehicle reaches the speed desired, push the SET (-)
button and release. The instrument cluster display will show
the set speed.
If the system is set when the vehicle speed is below 20 mph
(32 km/h), the set speed shall be defaulted to 20 mph
(32 km/h). If the system is set when the vehicle speed is
above 20 mph (32 km/h), the set speed shall be the current
speed of the vehicle.
NOTE:
ACC cannot be set if there is a stationary vehicle in front of
your vehicle in close proximity.
Remove your foot from the accelerator pedal, after the ACC
has been set. If you do not, the vehicle may continue to accel -
erate beyond the set speed. If this occurs:
• The message “ACC DRIVER OVERRIDE” will display in
the instrument cluster display.
• The system will not be controlling the distance between
your vehicle and the vehicle ahead. The vehicle speed will
only be determined by the position of the accelerator
pedal. To Cancel
The following conditions cancel the system:
• The brake pedal is applied.
• The CANC (cancel) button is pushed.
• An Anti-Lock Brake System (ABS) event occurs.
• The gear selector is removed from the DRIVE position.
• The Electronic Stability Control/Traction Control System
(ESC/TCS) activates.
• The vehicle parking brake is applied.
• Driver seatbelt is unbuckled at low speeds.
• Driver door is opened at low speeds.
• A Trailer Sway Control (TSC) event occurs.
• The driver switches ESC to full-off mode.
• The braking temperature exceeds normal range (over -
heated).

294 STARTING AND OPERATING
• If the button is continually pushed, the set speed will
continue to increase in 5 mph increments until the button
is released. The increase in set speed is reflected in the
instrument cluster display.
Metric Speed (km/h)
• Pushing the RES (+) button once will result in a 1 km/h
increase in set speed. Each subsequent 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 in 10 km/h increments until the
button is released. The increase in set speed is reflected in
the instrument cluster display.
To Decrease Speed
While ACC is set, the set speed can be decreased by pushing
the SET (-) button.
The speed decrement shown is dependant 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 subsequent tap of the button
results in a decrease of 1 mph. • If the button is continually pushed, the set speed will
continue to decrease in 5 mph increments until the button
is released. The decrease in set speed is reflected in the
instrument cluster display.
Metric Speed (km/h)
• Pushing the SET (-) button once will result in a 1 km/h
decrease in set speed. Each subsequent 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 in 10 km/h increments until the
button is released. The decrease in set speed is reflected in
the instrument cluster display.
NOTE:
• When you override and push the RES (+) button or SET (-)
buttons, the new set speed will be the current speed of the
vehicle.
• When you use the SET (-) button to decelerate, if the
engine’s braking power does not slow the vehicle suffi -
ciently to reach the set speed, the brake system will auto -
matically slow the vehicle.