2020 Ram 3500 differential

6
AUTOMATIC TRANSMISSION .......................... 233Ignition Park Interlock ...............................234
Brake/Transmission Shift Interlock
System .......................................................235 Eight-Speed Automatic Transmission —
If Equipped .................................................235 Six-Speed Automatic Transmission —
If Equipped .................................................239
AUXILIARY SWITCHES — IF EQUIPPED ........... 246
ACTIVE NOISE CANCELLATION ........................ 246
FOUR-WHEEL DRIVE OPERATION —
IF EQUIPPED ...................................................... 246
Electronically Shifted Transfer Case (Eight
Speed Transmission) — If Equipped ........246 Electronically Shifted Transfer Case (Six
Speed Transmission) — If Equipped ........250 Manually Shifted Transfer Case —
If Equipped .................................................253
AIR SUSPENSION SYSTEM — IF EQUIPPED.... 256
Description .................................................256
Air Suspension Modes...............................256
Instrument Cluster Display Messages......257Operation....................................................258 AXLE LOCKER SYSTEM — POWER WAGON
MODELS ONLY (IF EQUIPPED).......................... 258
STABILIZER/SWAY BAR SYSTEM — POWER
WAGON ONLY ....................................................260
SAFE OFF-ROAD DRIVING — POWER WAGON
ONLY ...................................................................261
Off-Road Driving Tips And Vehicle
Characteristics ........................................... 261 Driving In Snow, Mud And Sand ............... 262
Crossing Obstacles (Rocks And Other
High Points) ................................................ 263 Hill Climbing ............................................... 264Driving Through Water............................... 266Airing Down For Off-Road Driving ............. 267Vehicle Recovery........................................ 268
After Driving Off-Road ................................ 270
LIMITED-SLIP DIFFERENTIAL ........................... 270
WINCH USAGE — POWER WAGON ONLY
(IF EQUIPPED) .....................................................271
Things To Know Before Using
Your Winch ................................................. 271 Understanding The Features Of
Your Winch ................................................. 271 Winch Accessories .................................... 272
Operating Your Winch ............................... 273Rigging Techniques .................................. 279 FUEL SAVER TECHNOLOGY — GAS ENGINE
(IF EQUIPPED) .................................................... 279
SPEED CONTROL .............................................. 280
To Activate.................................................. 280
To Set A Desired Speed ............................ 280To Vary The Speed Setting ........................ 280
To Accelerate For Passing ........................ 281
To Resume Speed ..................................... 281
To Deactivate ............................................. 281 ADAPTIVE CRUISE CONTROL (ACC) —
IF EQUIPPED
....................................................... 282

Adaptive Cruise Control (ACC) Operation ... 283
Activating Adaptive Cruise Control (ACC) ... 284

To Activate/Deactivate.............................. 284
To Set A Desired ACC Speed..................... 285
To Cancel ................................................... 285
To Turn Off ................................................. 285
To Resume ................................................. 285To Vary The Speed Setting ........................ 286
Setting The Following Distance In ACC .... 287
Overtake Aid............................................... 288
ACC Operation At Stop............................... 289Adaptive Cruise Control (ACC) Menu ........ 289
Display Warnings And Maintenance ........ 290
Precautions While Driving With ACC......... 291
General Information .................................. 294
Normal (Fixed Speed) Cruise Control
Mode .......................................................... 294

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SAFETY153
Traction Control System (TCS)
This system monitors the amount of wheel spin
of each of the driven wheels. If wheel spin is
detected, the Traction Control System (TCS)
may apply brake pressure to the spinning
wheel(s) and/or reduce engine power to provide
enhanced acceleration and stability. A feature
of the TCS, Brake Limited Differential (BLD),
functions similar to a limited slip differential
and controls the wheel spin across a driven
axle. If one wheel on a driven axle is spinning
faster than the other, the system will apply the
brake of the spinning wheel. This will allow more
engine power to be applied to the wheel that is
not spinning. BLD may remain enabled even if
TCS and Electronic Stability Control (ESC) are in
a reduced mode.
Trailer Sway Control (TSC)
Trailer Sway Control (TSC) uses sensors in the
vehicle to recognize an excessively swaying
trailer and will take the appropriate actions to
attempt to stop the sway. TSC will become active automatically once an excessively
swaying trailer is recognized.
NOTE:
TSC cannot stop all trailers from swaying.
Always use caution when towing a trailer and
follow the trailer tongue weight recommenda
-
tions. Refer to “Trailer Towing” in “Starting And
Operating” for further information.
When TSC is functioning, the “ESC Activation/
Malfunction Indicator Light” will flash, the
engine power may be reduced and you may feel
the brakes being applied to individual wheels to
attempt to stop the trailer from swaying. TSC is
disabled when the ESC system is in the “Partial
Off” or “Full Off” modes.
AUXILIARY DRIVING SYSTEMS
BLIND SPOT MONITORING (BSM) — IF
E
QUIPPED
The Blind Spot Monitoring (BSM) system uses
two radar-based sensors, located inside the
taillights, to detect highway licensable vehicles
(automobiles, trucks, motorcycles, etc.) that
enter the blind spot zones from the rear/front/
side of the vehicle.

Rear Detection Zones

When the vehicle is started, the BSM warning
light will momentarily illuminate in both outside
rearview mirrors to let the driver know that the
system is operational. The BSM system sensors
WARNING!
If TSC activates while driving, slow the vehicle
down, stop at the nearest safe location, and
adjust the trailer load to eliminate trailer
sway.
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258STARTING AND OPERATING
(Continued)
OPERATION
Pushing the Alternate Trailer Height (ATH)
button once while at Normal Ride Height (NRH),
will lower the vehicle to Alternate Trailer Height
(ATH) and will illuminate the LED.
NOTE:
The LED will continuously blink until vehicle
Alternate Trailer Height (ATH) has been
achieved and the LED will turn on.
Pushing the Alternate Trailer Height (ATH) again
will raise the vehicle to Normal Ride Height
(NRH).
NOTE:
The LED will continuously blink until Normal
Ride Height (NRH) has been achieved and the
LED will turn off.
Transport Mode – No indicator lamps will be
illuminated. Transport Mode is disabled by
driving the vehicle, or deselecting the mode
via the interface.
Tire/Jack Mode – No indicator lamps will be
illuminated. Tire/Jack Mode is disabled by
driving the vehicle, or by deselecting the
mode via the interface.
Wheel Alignment Mode – No indicator lamps
will be illuminated. Wheel Alignment Mode is
disabled by driving the vehicle, or by dese-
lecting the mode via the interface.
Bed Lowering Mode – Telltale on the cluster
will be illuminated. Bed Lowering Mode is
disabled by driving the vehicle, or deselecting
the mode via the interface.
AXLE LOCKER SYSTEM — POWER WAGON
MODELS ONLY (IF EQUIPPED)
This vehicle is equipped with electronically
locking front and rear differentials. These
differentials, when engaged, mechanically lock
together the axle shafts forcing the wheels to
spin at an equal rate. This allows the vehicle to
maintain its momentum and prevents it from
becoming stuck. The locking front and rear
differentials should only be engaged during
low-speed, extreme off-road situations where
one wheel is likely to not be in contact with the
ground. It is not recommended to drive the
vehicle with the differentials locked on pavement due to the reduced ability to turn and
speed limitations.

Axle Lock Selector

1 — FRONT/REAR LOCK – the front and rear axles
are locked
2 — REAR LOCK – the rear axle is locked
3 — AXLE UNLOCK – the front and rear axles are
unlocked
CAUTION!
Do not lock the front or rear axle on hard
surfaced roads. The ability to steer the
vehicle is reduced and damage to the drive -
train may occur when the axles are locked
on hard surfaced roads.

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STARTING AND OPERATING259
The locking axles are controlled by the axle lock
buttons.
Under normal driving conditions, the vehicle
should be left in the AXLE UNLOCK position.
NOTE:
Even when the axles are in the AXLE UNLOCK
position, the limited slip differential in the rear
axle still provides torque biasing capability for
moderate low traction environments.
During the command to lock the axle, the
indicator light will flash until the axle is locked.
After the lock command has been successfully
executed, the light will remain on solid. To lock the rear axle, place the vehicle in 4WD
LOW, 4WD HIGH or 2WD. Refer to “Four Wheel
Drive Operation” in “Starting And Operating” for
further information. Push the REAR LOCK
button while traveling less than 10 mph
(16 km/h). The REAR LOCK indicator light will
remain on when the rear axle is locked.
NOTE:
Left to right wheel speed difference may be
necessary to allow the axle to fully lock. If the
indicator light is flashing after placing the
vehicle in the REAR LOCK or FRONT/REAR LOCK
position, drive the vehicle in a turn or on loose
gravel to expedite the locking action.
To lock the front axle, push the FRONT/REAR
LOCK button while traveling less than 10 mph
(16 km/h) in 4WD LOW. The FRONT/REAR
LOCK indicator light will be solid when the front
axle is locked.
NOTE:
The rear axle must be locked before the front
axle will lock.
When both the axles are locked, to unlock the
front axle, push the REAR LOCK button while in
4WD LOW. The FRONT/REAR LOCK indicator
light will go out when the axle is unlocked.
NOTE:
The axle lockers could be torque locked due to
side to side loads on the axle. Driving slowly
while turning the steering wheel from a left
hand turn to a right hand turn or driving in
REVERSE for a short distance may be required
to release the torque lock and unlock the axles.
To unlock the rear axle, push the AXLE UNLOCK
button. The REAR LOCK indicator light will go
out when the rear axle is unlocked.
Do not try to lock the rear axle if the vehicle
is stuck and the tires are spinning. You can
damage drivetrain components. Lock the
rear axle before attempting situations or
navigating terrain, which could possibly
cause the vehicle to become stuck.
CAUTION!
(Continued)
WARNING!
Do not use the locked axle position for normal
driving. A locked front axle is intended for
off-road driving only. Locking the front axle
during on-road driving will reduce the steering
ability. This could cause a collision and you
may be seriously injured.
5

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266STARTING AND OPERATING
If You Stall Or Begin To Lose Headway – If you
stall or begin to lose headway while climbing
a steep hill, allow your vehicle to come to a
stop and immediately apply the brake.
Restart the engine and shift into REVERSE.
Back slowly down the hill allowing the
compression braking of the engine and trans -
mission to help regulate your speed. If the
brakes are required to control vehicle speed,
apply them lightly and avoid locking or skid-
ding the tires.DRIVING THROUGH WATER
Extreme care should be taken crossing any type
of water. Water crossings should be avoided if
possible and only be attempted when
necessary, in a safe responsible manner. You
should only drive through areas which are
designated and approved. You should tread
lightly and avoid damage to the environment.
You should know your vehicle's abilities and be
able to recover it if something goes wrong. You
should never stop or shut a vehicle off when
crossing deep water unless you ingested water
into the engine air intake. If the engine stalls do
not attempt to restart it. Determine if it has
ingested water first. The key to any crossing is
low and slow. You want to use FIRST gear in
4WD LOW and proceed very slowly with a
constant slow speed (3-5 mph [5–8 km/h]
maximum) and light throttle. Keep the vehicle
moving; do not try to accelerate through the
crossing. After crossing any water higher than
the bottom of the axle differentials, you should
inspect all of the vehicle fluids for signs of water
ingestion.
Before You Cross Any Type Of Water – As you
approach any type of water you need to
determine if you can cross it safely and
responsibly. If necessary, get out and walk
through the water or probe it with a stick. You
need to be sure of its depth, approach angle,
current and bottom condition. Be careful of
murky or muddy waters, check for hidden
obstacles. Make sure you will not be
intruding on any wildlife and you can recover
the vehicle if necessary. The key to a safe
crossing is the water depth, current and
bottom conditions. On soft bottoms the
vehicle will sink in, effectively increasing the
water level on the vehicle. Be sure to
consider this when determining the depth
and the ability to safely cross.
WARNING!
If the engine stalls or you lose headway or
cannot make it to the top of a steep hill or
grade, never attempt to turn around. To do so
may result in tipping and rolling the vehicle,
which may result in severe injury. Always back
carefully straight down a hill in REVERSE.
Never back down a hill in NEUTRAL using only
the vehicle brakes. Never drive diagonally
across a hill, always drive straight up or down.
CAUTION!
Water ingestion into the axles, transmission,
transfer case, engine or vehicle interior can
occur if you drive too fast or through too deep
of water. Water can cause permanent
damage to engine, driveline or other vehicle
components and your brakes will be less
effective once wet and/or muddy.

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270STARTING AND OPERATING
AFTER DRIVING OFF-ROAD
Off-road operation puts more stress on your
vehicle than does most on-road driving. After
going off-road, it is always a good idea to check
for damage. That way you can get any problems
taken care of right away and have your vehicle
ready when you need it.
Completely inspect the underbody of your
vehicle. Check tires, body structure, steering,
suspension, and exhaust system for damage.
Inspect the radiator for mud and debris and
clean as required.
Check threaded fasteners for looseness,
particularly on the chassis, drivetrain compo -
nents, steering, and suspension. Retighten them, if required, and torque to the values
specified in the Service Manual.
Check for accumulations of plants or brush.
These things could be a fire hazard. They
might hide damage to fuel lines, brake hoses,
axle pinion seals, and propeller shafts.
After extended operation in mud, sand,
water, or similar dirty conditions, have the
radiator, fan, brake rotors, wheels, brake
linings, and axle yokes inspected and
cleaned as soon as possible.
If you experience unusual vibration after
driving in mud, slush or similar conditions,
check the wheels for impacted material.
Impacted material can cause a wheel imbal-
ance and freeing the wheels of it will correct
the situation.
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.

WARNING!
Winch cables are under high tension when in
use and can become a projectile if they fail.
Never stand over or straddle the winch cable.
Never jerk or overload the winch cable. Never
stand in front of the vehicle while winching.
Failure to follow these instructions can result
in serious or fatal injury.
WARNING!
Abrasive material in any part of the brakes
may cause excessive wear or unpredictable
braking. You might not have full braking
power when you need it to prevent a collision.
If you have been operating your vehicle in
dirty conditions, get your brakes checked and
cleaned as necessary.
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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424SERVICING AND MAINTENANCE
8. Reinsert the dipstick. Check for leaks.
Release the parking brake.
NOTE:
If it is necessary to check the transmission
below the operating temperature, the fluid level
should be between the two COLD (lower) holes
on the dipstick with the fluid at 68-86°F /
20-30°C. Only use the COLD region of the
dipstick as a rough reference when setting the
fluid level after a transmission service or fluid
change. Re-check the fluid level, and adjust as
required, once the transmission reaches
normal operating temperature.
Fluid And Filter Changes — Eight-Speed
Transmission
Under normal operating conditions, the fluid
installed at the factory will provide satisfactory
lubrication for the life of the vehicle.
Routine fluid and filter changes are not
required. However, change the fluid and filter if
the fluid becomes contaminated (with water,
etc.), or if the transmission is disassembled for
any reason.
Fluid And Filter Changes — Six Speed
Transmission
Refer to the “Maintenance Plan” for the proper
maintenance intervals.
In addition, change the fluid and filters if the
fluid becomes contaminated (with water, etc.),
or if the transmission is disassembled for any
reason.
REAR AXLE AND 4X4 FRONT DRIVING
A
XLE FLUID LEVEL
For normal service, periodic fluid level checks
are not required. When the vehicle is serviced
for other reasons the exterior surfaces of the
axle assembly should be inspected. If gear oil
leakage is suspected inspect the fluid level. Refer to “Fluids And Lubricants” in “Technical
Specifications” for further information. This
inspection should be made with the vehicle in a
level position.
For all 2500/3500 Model axles, the fluid level
should be 1/4 in ± 1/4 in (6.4 mm ± 6.4 mm)
below the fill hole on the 9.25 in front, 11.5 in
rear axle, and 12.0 in rear axle.
Drain And Refill
Refer to the “Maintenance Plan” for the proper
maintenance intervals.
Lubricant Selection
Refer to “Fluids And Lubricants” in “Technical
Specifications” for further information.
NOTE:
The presence of water in the gear lubricant will
result in corrosion and possible failure of differ -
ential components. Operation of the vehicle in
water, as may be encountered in some
off-highway types of service, will require
draining and refilling the axle to avoid damage.
Limited-Slip Differentials DO REQUIRE limited
slip oil additive (friction modifiers).
CAUTION!
If the fluid temperature is below 50°F (10°C)
it may not register on the dipstick. Do not add
fluid until the temperature is elevated enough
to produce an accurate reading. Run the
engine at idle, in PARK, to warm the fluid.
CAUTION!
If the fluid temperature is below 50°F (10°C)
it may not register on the dipstick. Do not add
fluid until the temperature is elevated enough
to produce an accurate reading. Run the
engine at idle, in PARK, to warm the fluid.

20_DJD2_OM_EN_USC_t.book Page 424

SERVICING AND MAINTENANCE425
NOTE:
Slight noise and mild shuddering may be
evident while turning a vehicle with limited slip
differential on concrete or dry pavement. These
conditions should be considered normal opera -
tion of the limited slip differential.
TRANSFER CASE
Selection Of Lubricant
Use only the manufacturer's recommended
fluid. Refer to “Fluids And Lubricants” in
“Technical Specifications” for further
information.
Fluid Level Check
This fluid level can be checked by removing the
filler plug. The fluid level should be to the
bottom edge of the filler plug hole with the
vehicle in a level position.
Drain And Refill
Refer to the “Maintenance Plan” in this section
for the proper maintenance intervals.
NOISE CONTROL SYSTEM REQUIRED
M
AINTENANCE & WARRANTY
All vehicles built over 10,000 lbs. (4,535 kg)
Gross Vehicle Weight Rating and manufactured
for sale and use in the United States are
required to comply with the Federal
Government's Exterior Noise Regulations.
These vehicles can be identified by the Noise
Emission Control Label located in the operator's
compartment.
Required Maintenance For Noise Control
Systems

The following maintenance services must be
performed every six months or 7,500 miles
(12,000 km) whichever comes first, to ensure
proper operation of the noise control systems.
In addition, inspection and service should be
performed anytime a malfunction is observed
or suspected. Proper maintenance of the
entire vehicle will help the effectiveness of the
noise control systems.

Exhaust System
Inspect the entire exhaust system for leaks and
damaged parts. Devices such as hangers,
clamps, and U-bolts should be tight and in good
condition. Damaged components, burned or
blown out mufflers, burned or rusted out
exhaust pipes should be replaced according to
the procedures and specifications outlined in
the appropriate service manual.
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