axle Ram 2500 2020 User Guide

228STARTING AND OPERATING
The block heater must be plugged in at least
one hour to have an adequate warming effect
on the coolant.
NOTE:
The block heater will require 110 Volts AC and
6.5 Amps to activate the heater element.
Block Heater Usage
For ambient temperatures below 0°F (-18°C),
engine block heater usage is recommended.
For ambient temperatures below –20°F
(-29°C), engine block heater usage is required.
ENGINE BREAK-IN RECOMMENDATIONS —
GAS ENGINE
A long break-in period is not required for the
engine and drivetrain (transmission and axle) in
your vehicle.
Drive moderately during the first 300 miles
(500 km). After the initial 60 miles (100 km), speeds up to 50 or 55 mph (80 or 90 km/h) are
desirable.
While cruising, brief full-throttle acceleration
within the limits of local traffic laws contributes
to a good break-in. Wide-open throttle accelera-
tion in low gear can be detrimental and should
be avoided.
The engine oil installed in the engine at the
factory is a high-quality energy conserving type
lubricant. Oil changes should be consistent with
anticipated climate conditions under which
vehicle operations will occur. For the recom
-
mended viscosity and quality grades, refer to
“Fluids And Lubricants” in “Technical Specifica-
tions”.
NOTE:
A new engine may consume some oil during its
first few thousand miles (kilometers) of opera -
tion. This should be considered a normal part of
the break-in and not interpreted as a problem.
Please check your oil level with the engine oil indicator often during the break in period. Add
oil as required.
ENGINE BREAK-IN RECOMMENDATIONS —
DIESEL ENGINE
The Cummins® Turbo Diesel engine does not
require a break-in period due to its construction.
Normal operation is allowed, providing the
following recommendations are followed:
Warm up the engine before placing it under
load.
Do not operate the engine at idle for
prolonged periods.
Use the appropriate transmission gear to
prevent engine lugging.
Observe vehicle oil pressure and tempera
-
ture indicators.
Check the coolant and oil levels frequently.
Vary throttle position at highway speeds
when carrying or towing significant weight.
WARNING!
Remember to disconnect the cord before
driving. Damage to the 110–115 Volt
electrical cord could cause electrocution.
CAUTION!
Never use Non-Detergent Oil or Straight
Mineral Oil in the engine or damage may
result.

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STARTING AND OPERATING245
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 2WD will have greater fuel
economy benefits as the front axle is not
engaged in 2WD.
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 pushing the desired position
on the 4WD control switch.
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 in
the center of the 4WD Control Switch and is
pushed by using a ballpoint pen or similar
object. 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 HIGH 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. To find the
shift requirements, refer to the “Shifting Proce-
dure” for your transfer case, located in this
section.
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.
WARNING! (Continued)
5

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250STARTING AND OPERATING
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.
AIR SUSPENSION SYSTEM — IF EQUIPPED
Description
This air suspension system is a rear leveling ride
height system. The main purpose of this system
is to maintain the truck’s rear ride height level.
There are two selectable heights that can be
chosen based on your operating conditions.
The system requires that the ignition be in the
ON/RUN position or the engine running with
zero vehicle speed for all user requested
changes and load leveling.
Rear Leveling Ride Height Switch

Normal Ride Height (NRH) – This is the standard
position of the suspension and is meant for
normal driving. It will automatically adjust to
maintain the rear ride height as conditions
change.
Alternate Trailer Height (ATH) – Lowers the
vehicle approximately 1 inch (25 mm) for a level
truck, to be used as required while trailer
towing. It will automatically adjust to maintain
the rear ride height as conditions change.
Trailer Decoupling/Unloading - The air suspen-
sion system will continue to load level after the
vehicle has been turned off for 10 minutes
without compressor activation. This allows for
easy removal of a trailer and/or load from the
back of the truck by maintaining the ride height.
After 10 minutes you will need to turn the igni -tion to the run position for the air suspension to
re-level due to addition/removal of load in the
vehicle. If the air suspension system is disabled
using the settings menu (Tire Jack Mode, Trans
-
port Mode, Alignment Mode, or Bed Lowering
Mode) the system will remain disabled when
the vehicle is turned off. Reactivating the air
suspension can be accomplished via the
settings menu or driving the vehicle above
5 mph (8 km/h) for Tire Jack Mode, Alignment
Mode, Transport Mode and Bed Lowering
Mode.
NOTE:
Most 3500 models will not lower to Alternate
Trailer Height (ATH) when unloaded.
Refer to “Trailer Towing” in “Starting And
Operating” for further information.
WARNING!
The air suspension system uses a high
pressure volume of air to operate the system.
To avoid personal injury or damage to the
system, see your authorized dealer for
service.

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252STARTING AND OPERATING
(Continued)
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 differ -
entials, 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 pave -
ment 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 OPERATING253
The locking axles are controlled by the axle
locker switch.
Under normal driving conditions, the switch
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 indi -
cator 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 RR 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 switch
in the REAR LOCK or FRONT/REAR LOCK posi
-
tion, 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 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.
STABILIZER/SWAY BAR SYSTEM — POWER
WAGON ONLY
Your vehicle is equipped with an electronic
disconnecting stabilizer/sway bar. This system
allows greater front suspension travel in
off-road situations.
Due to the use of taller springs, this vehicle has
an increased ride height of approximately
1.9 inches (48.3 mm) in the front and
1.5 inches (38.1 mm) in the rear. A major
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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STARTING AND OPERATING257
key to driving in soft sand is using the appro -
priate tire pressure, accelerating slowly,
avoiding abrupt maneuvers and maintaining
the vehicle's momentum. If you are going to
be driving on large soft sandy areas or dunes,
reduce your tire pressure to a minimum of
15 psi (103 kPa) to allow for a greater tire
surface area. Reduced tire pressure will dras -
tically improve your traction and handling,
while driving on the soft sand, but you must
return the tires to normal air pressure before
driving on pavement or other hard surfaces.
Be sure you have a way to air the tires back
up prior to reducing the pressure.
Crossing Obstacles (Rocks And Other High
Points)
While driving off road, you will encounter many
types of terrain. These varying types of terrain
bring different types of obstacles. Before
proceeding review the path ahead to determine the correct approach and your ability to safely
recover the vehicle if something goes wrong.
Keeping a firm grip on the steering wheel, bring
the vehicle to a complete stop and then inch the
vehicle forward until it makes contact with the
object. Apply the throttle lightly while holding a
light brake pressure and ease the vehicle up
and over the object.
Using A Spotter
There are many times where it is hard to see the
obstacle or determine the correct path. Deter
-
mining the correct path can be extremely diffi -
cult when you are confronting many obstacles.
In these cases have someone guide you over,
through, or around the obstacle. Have the
person stand a safe distance in front of you
where they can see the obstacle, watch your
tires and undercarriage, and guide you through.
Crossing Large Rocks
When approaching large rocks, choose a path
which ensures you drive over the largest with your tires. This will lift your undercarriage over
the obstacle. The tread of the tire is tougher and
thicker than the side wall and is designed to
take the abuse. Always look ahead and make
every effort to cross the large rocks with your
tires.
Crossing A Ravine, Gully, Ditch, Washout Or
Rut
When crossing a ravine, gully, ditch, washout or
a large rut, the angled approach is the key to
maintaining your vehicle's mobility. Approach
these obstacles at a 45-degree angle and let
each tire go through the obstacle inde
-
pendently. You need to use caution when
crossing large obstacles with steep sides. Do
not attempt to cross any large obstacle with
steep sides at an angle great enough to put the
vehicle at risk of a rollover. If you get caught in
a rut, dig a small trench to the right or left at a
45-degree angle ahead of the front tires. Use
CAUTION!
Reduced tire pressures may cause tire
unseating and total loss of air pressure. To
reduce the risk of tire unseating, while at a
reduced tire pressure, reduce your speed and
avoid sharp turns or abrupt maneuvers.
WARNING!
Crossing obstacles can cause abrupt steering
system loading which could cause you to
loose control of your vehicle.
CAUTION!
Never attempt to straddle a rock that is
large enough to strike your axles or under -
carriage.
Never attempt to drive over a rock which is
large enough to contact the door sills.5

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260STARTING AND OPERATING
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 neces -
sary, 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.
Crossing Puddles, Pools, Flooded Areas Or
Other Standing Water – Puddles, pools,
flooded or other standing water areas
normally contain murky or muddy waters.
These water types normally contain hidden
obstacles and make it difficult to determine
an accurate water depth, approach angle,
and bottom condition. Murky or muddy water
holes are where you want to hook up tow
straps prior to entering. This makes for a
faster, cleaner and easier vehicle recovery. If
you are able to determine you can safely
cross, than proceed using the low and slow
method.
Crossing Ditches, Streams, Shallow Rivers Or
Other Flowing Water – Flowing water can be
extremely dangerous. Never attempt to cross
a fast running stream or river even in shallow
water. Fast moving water can easily push
your vehicle downstream sweeping it out of
control. Even in very shallow water, a high
current can still wash the dirt out from
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.
CAUTION!
Muddy waters can reduce the cooling system
effectiveness by depositing debris onto the
radiator.

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264STARTING AND OPERATING
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 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.
WINCH USAGE — POWER WAGON ONLY (IF
EQUIPPED)
Things To Know Before Using Your Winch
General Winch Information
Your vehicle is equipped with an electric vehicle
recovery winch. This winch uses the electrical
power from the vehicle charging system to
power a motor that winds the winch rope onto
the winch drum via planetary gear reduction. By
nature, a winch is capable of generating very
high forces and should be used with care. Do
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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STARTING AND OPERATING317
3. Stop filling the DEF tank immediately when
any of the following happen: DEF stops
flowing from the fill bottle into the DEF tank,
DEF splashes out the filler neck, or a DEF
pump nozzle automatically shuts off.
4. Reinstall cap onto DEF tank.
Filling The Def Tank In Cold Climates
Since DEF will begin to freeze at 12°F (-11°C),
your vehicle is equipped with an automatic DEF
heating system. This allows the DEF injection system to operate properly at temperatures
below 12°F (-11°C). If your vehicle is not in
operation for an extended period of time with
temperatures below 12°F (-11°C), the DEF in
the tank may freeze. If the tank is overfilled and
freezes, it could be damaged. Therefore, do not
overfill the DEF tank.
Extra care should be taken when filling with
portable containers to avoid overfilling. Note the
level of the DEF gauge in your instrument cluster.
You may safely add a maximum of 2 Gallons
(7.5 Liters) of DEF from portable containers
when your DEF gauge is reading ½ full.
VEHICLE LOADING
Gross Vehicle Weight Rating (GVWR)
The GVWR is the total permissible weight of your
vehicle including driver, passengers, vehicle,
options and cargo. The label also specifies
maximum capacities of front and rear axle
systems (GAWR). Total load must be limited so
GVWR and front and rear GAWR are not
exceeded.
Payload
The payload of a vehicle is defined as the allow
-
able load weight a truck can carry, including the
weight of the driver, all passengers, options and
cargo.
Gross Axle Weight Rating (GAWR)
The GAWR is the maximum permissible load on
the front and rear axles. The load must be
distributed in the cargo area so that the GAWR
of each axle is not exceeded.
Each axle GAWR is determined by the compo -
nents in the system with the lowest load
carrying capacity (axle, springs, tires or wheels).
Heavier axles or suspension components some -
times specified by purchasers for increased
durability does not necessarily increase the
vehicle's GVWR.
Tire Size
The tire size on the Vehicle Certification Label
represents the actual tire size on your vehicle.
Replacement tires must be equal to the load
capacity of this tire size.
Never add anything other than DEF to the
tank – especially any form of hydrocarbon
such as diesel fuel, fuel system additives,
gasoline, or any other petroleum-based
product. Even a very small amount of these,
less than 100 parts per million or less than
1 oz. per 78 Gallons (295 Liters) will
contaminate the entire DEF system and will
require replacement. If owners use a
container, funnel or nozzle when refilling
the tank, it should either be new or one that
is has only been used for adding DEF.
Mopar provides an attachable nozzle with
its DEF for this purpose.
CAUTION! (Continued)
5

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318STARTING AND OPERATING
Rim Size
This is the rim size that is appropriate for the tire
size listed.
Inflation Pressure
This is the cold tire inflation pressure for your
vehicle for all loading conditions up to full
GAWR.
Curb Weight
The curb weight of a vehicle is defined as the
total weight of the vehicle with all fluids,
including vehicle fuel, at full capacity condi -
tions, and with no occupants or cargo loaded
into the vehicle. The front and rear curb weight
values are determined by weighing your vehicle
on a commercial scale before any occupants or
cargo are added.
Loading
The actual total weight and the weight of the
front and rear of your vehicle at the ground can
best be determined by weighing it when it is
loaded and ready for operation.
The entire vehicle should first be weighed on a
commercial scale to ensure that the GVWR has
not been exceeded. The weight on the front and
rear of the vehicle should then be determined separately to be sure that the load is properly
distributed over the front and rear axles.
Weighing the vehicle may show that the GAWR
of either the front or rear axle has been
exceeded but the total load is within the speci
-
fied GVWR. If so, weight must be shifted from
front to rear or rear to front as appropriate until
the specified weight limitations are met. Store
the heavier items down low and be sure that the
weight is distributed equally. Stow all loose
items securely before driving.
Improper weight distributions can have an
adverse effect on the way your vehicle steers
and handles and the way the brakes operate.
TRAILER TOWING
In this section you will find safety tips and infor -
mation on limits to the type of towing you can reasonably do with your vehicle. Before towing a
trailer, carefully review this information to tow
your load as efficiently and safely as possible.
To maintain the New Vehicle Limited Warranty
coverage, follow the requirements and recom
-
mendations in this manual concerning vehicles
used for trailer towing.
Common Towing Definitions
The following trailer towing-related definitions
will assist you in understanding the following
information:
Gross Vehicle Weight Rating (GVWR)
The GVWR is the total allowable weight of your
vehicle. This includes driver, passengers, cargo
and tongue weight. The total load must be
limited so that you do not exceed the GVWR.
Refer to “Vehicle Loading/Vehicle Certification
Label” in “Starting And Operating” for further
information.
Gross Trailer Weight (GTW)
The GTW is the weight of the trailer plus the
weight of all cargo, consumables and equip -
ment (permanent or temporary) loaded in or on
the trailer in its "loaded and ready for operation"
condition.
CAUTION!
Do not load your vehicle any heavier than the
GVWR or the maximum front and rear GAWR.
If you do, parts on your vehicle can break, or
it can change the way your vehicle handles.
This could cause you to lose control. Also
overloading can shorten the life of your
vehicle.

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