tow Ram 2500 2020 Repair Manual

244STARTING AND OPERATING
(Continued)
FOUR-WHEEL DRIVE OPERATION — IF
EQUIPPED
Four-wheel drive trucks are equipped with
either a manually shifted transfer case or an
electronically shifted transfer case. Refer to the
operating instructions for your transfer case,
located in this section for further information.
Four-Position Electronically Shifted Transfer
Case — 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.

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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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STARTING AND OPERATING247
2WD Or 4WD HIGH To 4WD LOW
NOTE:
When shifting into or out of 4WD LOW some
gear noise may be heard. This noise is normal
and is not detrimental to the vehicle or occu -
pants.
Shifting can be performed with the vehicle
rolling 2 to 3 mph (3 to 5 km/h) or completely
stopped. You can use either of the following
procedures:
Preferred Procedure

1. With the engine running, slow the vehicle to 2 to 3 mph (3 to 5 km/h).

2. Shift the transmission into NEUTRAL.
3. While still rolling, push the desired position on the transfer case control switch.
4. After the desired position indicator light is on (not flashing), shift the transmission
back into gear. Alternate Procedure

1. Bring the vehicle to a complete stop.

2. With the ignition switch in the ON position
and the engine running, shift the transmis -
sion into NEUTRAL.
3. Push the desired position on the transfer case control switch.
4. After the desired position indicator light is on (not flashing), shift the transmission
back into gear.
NOTE:
If Steps 1 or 2 of either the Preferred or Alter -
nate Procedure are not satisfied prior to
attempting the shift, then the desired posi -
tion indicator light will flash continuously
while the original position indicator light is
on, until all requirements have been met.
The ignition switch must be in the ON position
for a shift to take place and for the position
indicator lights to be operable. If the ignition
switch is not in the ON position, the shift will
not take place and no position indicator lights
will be on or flashing.
Manually Shifted Transfer Case — If
Equipped
The transfer case provides four mode positions:
Two-Wheel Drive High Range (2H)
Four-Wheel Drive Lock High Range (4H)
N (Neutral)
Four-Wheel Drive Low Range (4L)
For additional information on the appropriate
use of each transfer case mode position, see
the information below:
2H
Two-Wheel Drive High Range — This range is for
normal street and highway driving on dry, hard
surfaced roads.
4H
Four-Wheel Drive Lock 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, slip -
pery road surfaces only.
N (Neutral)
N (Neutral) — This range disengages both the
front and rear driveshafts from the powertrain.
To be used for flat towing behind another
5

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248STARTING AND OPERATING
vehicle. Refer to “Recreational Towing” in
“Starting And Operating” for further informa -
tion.
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).
This transfer case is intended to be driven in the
2H position for normal street and highway
conditions such as dry, hard surfaced roads.
When additional traction is required, the 4H and
4L positions can be used to lock the front and
rear driveshafts together and force the front
and rear wheels to rotate at the same speed.
This is accomplished by simply moving the gear
selector to the desired positions once the
appropriate speed and gear requirements are
met. Refer to “Shifting Procedure – Manually
Shifted Transfer Case” in this section for further
information.
The 4H and 4L positions are intended for loose,
slippery road surfaces only. Driving in the 4H
and 4L positions on dry, hard surfaced roads may cause increased tire wear and damage to
the driveline components.
The “Transfer Case Position Indicator Light” in
the instrument cluster will alert the driver that
the vehicle is in four-wheel drive and that the
front and rear driveshafts are locked together.
This light will illuminate when the transfer case
is shifted into either the 4H or 4L position. There
is no light for the 2H or NEUTRAL positions on
some models.
When operating your vehicle in 4L, the engine
speed is approximately three times that of the
2H or 4H 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 will
adversely affect shifting and can cause damage
to the drivetrain.
NOTE:
Do not attempt to make a shift while only the
front or rear wheels are spinning, as this can
cause damage to driveline components. Because four-wheel drive provides improved
traction, there is a tendency to exceed safe
turning and stopping speeds. Do not go faster
than road conditions permit.
NOTE:
Delayed shifts out of four-wheel drive may be
experienced due to uneven tire wear, low or
uneven tire pressures, excessive vehicle
loading, or cold temperatures.
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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STARTING AND OPERATING249
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)
N (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 4WD LOW some
gear noise may be heard. This noise is normal
and is not detrimental to the vehicle or occu -
pants.
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 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 4WD LOW 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 4WD LOW with the
vehicle moving faster than 2 to 3 mph (3 to
5 km/h).
Do not attempt to shift into or out of 4WD
LOW while the transmission is in gear.
CAUTION!
Do not use 4L (Low) range when operating
the vehicle on dry pavement. Driveline
hardware damage can result.
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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STARTING AND OPERATING251
Air Suspension Modes
The air suspension system has multiple modes
to protect the system in unique situations:
Tire/Jack Mode
To assist with changing a tire, the air suspen -
sion system has a feature which allows the
automatic leveling to be disabled. This mode is
intended to be enabled with the engine running.
Refer to “Instrument Cluster Display” in
“Getting To Know Your Instrument Panel” or
“Uconnect Settings” in “Multimedia” (if
equipped with a touch screen radio) for further
information.
NOTE:
This mode is intended to be enabled with the
engine running.
Transport Mode
For towing your vehicle with four wheels off the
road, the air suspension system has a feature
which will put the vehicle below Normal Ride
Height (NRH) and disable the automatic load
leveling system. This mode is intended to be
enabled with engine running. Refer to “Instru -
ment Cluster Display” in “Getting To Know Your
Instrument Panel” or “Uconnect Settings” in
“Understanding Your Instrument Panel” if equipped with a touch screen radio for further
information.
NOTE:
This mode is intended to be enabled with the
engine running.
Wheel Alignment Mode
Before performing a wheel alignment this mode
must be enabled. Refer to “Instrument Cluster
Display” in “Getting To Know Your Instrument
Panel” or “Uconnect Settings” in “Multimedia”
(if equipped with a touch screen radio) for
further information.
NOTE:
This mode is intended to be enabled with the
engine running.
Bed Lowering Mode
This setting is used to lower the rear suspension
to the lowest possible height and disable the air
suspension system. It enables easier loading/
unloading of the truck and makes it easier to
hook up trailers. Refer to “Instrument Cluster
Display” in “Getting To Know Your Instrument
Panel” or “Uconnect Settings” in “Under
-
standing Your Instrument Panel” if equipped with a touch screen radio for further informa
-
tion.
Protection Strategy
In order to “protect” the air suspension system,
the vehicle will disable load leveling as required
(suspension overloaded, battery charge low,
etc.). Load leveling will automatically resume as
soon as system operation requirements are
met. See your authorized dealer if system does
not resume.
Instrument Cluster Display Messages
When the appropriate conditions exist, a
message will appear in the instrument cluster
display. Refer to “Instrument Cluster Display” in
“Getting To Know Your Instrument Panel” for
further information.
An audible chime will be heard whenever a
system error has been detected.
See your authorized dealer for system service if
normal operation does not resume.
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.
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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STARTING AND OPERATING261
around your tires putting you and your vehicle
in jeopardy. There is still a high risk of
personal injury and vehicle damage with
slower water currents in depths greater than
the vehicle's running ground clearance. You
should never attempt to cross flowing water
which is deeper than the vehicle's running
ground clearance. Even the slowest current
can push the heaviest vehicle downstream
out of control if the water is deep enough to
push on the large surface area of the
vehicle's body. Before you proceed deter -
mine the speed of the current, the water's
depth, approach angle, bottom condition and
if there are any obstacles, then cross at an
angle heading slightly upstream using the
low and slow technique.Airing Down For Off-Road Driving
Running lower tire pressure off-road can
improve your ride comfort and vehicle traction.
Reducing the tire air pressure allows the tire to
bulge slightly, improving its surface area for
better flotation and ability to mold or form to the
ground contour. Different terrain, tires, and
vehicles require different tire pressure. Hard
surfaces like rock and heavier vehicles require
higher pressures than softer surfaces such as
sand and lighter vehicles. You will need to
experiment to determine what is right for your
situation. It is easier and faster to let air out
than it is to replace it. Start high and lower it as
required. Remember you must return the tires
to normal air pressure before driving on road or
at highway conditions. Be sure you have a way
to return the tires to their normal on road air
pressure.
Vehicle Recovery
If you drive off-road, you may encounter a situa-
tion where you will need to recover your vehicle.
Vehicle recovery should always be given consid -
eration before attempting a questionable
obstacle. You should never go off-road driving
without the ability to recover your vehicle from a
situation. Having another vehicle with you
usually works best for most situations. The first
thing to do is assess the situation. Why are you
stuck? Are you hung up on something? Would it
be easier to go forward or to go backward? Can
you still move the vehicle? Is there an anchor
point to winch to? Are you alone or do you have
another vehicle to help? Is there high risk of
vehicle damage during the recovery process?
Answering these questions will help you deter -
mine the best method of recovery. If you can still
move the vehicle slightly and the only issue is
slick ground, then rock cycling your vehicle
would be the first choice. If you have ample
room, an additional vehicle and there is low risk
of vehicle impact on the surroundings, then
using a tow strap to the vehicle tow hooks would
be fast and easy. If the vehicle is severely hung
up or in a situation where great care needs to be
taken during the recovery, then nothing can do
the job better than a winch. If you are severely
WARNING!
Never drive through fast moving deep water. It
can push your vehicle downstream, sweeping
it out of control. This could put you and your
passengers at risk of injury or drowning.
CAUTION!
Reduced tire pressure increases the risk of
tire damage and may cause tire unseating
with total loss of air pressure. To reduce the
risk of tire unseating, while at a reduced tire
pressure, drive at slower speeds and avoid
sharp turns or abrupt maneuvers.
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262STARTING AND OPERATING
hung up on something you should jack the
vehicle up and stack something under the
wheels to allow the vehicle to roll off the object
without causing further damage. This should be
tried before attempting any recovery method.
Rock Cycling Your Vehicle – Rock cycling your
vehicle is one of the easiest, fastest and
most commonly used methods. This simply
involves shifting your vehicle from DRIVE to
REVERSE, while applying throttle after each
shift. During this process, for additional trac -
tion, try turning your steering wheel quickly
left and right no more than a quarter turn. If
you are stuck in mud, sand, or snow try spin -
ning your tires during this process to clean
the debris from the tread and improve the
traction. You want to create a rocking motion
with the vehicle. This helps build vehicle
momentum, which hopefully gets you out.
Remember to ease off and on the accelerator before and after the shift. If after a few rock
cycles your vehicle is not free, stop and try
another method of recovery. Continuous rock
cycling will only cause unnecessary damage
to your vehicle and the environment.
Using The Tow Hooks With A Tow Strap
– Tow
straps are a quick and easy way to recover
your vehicle from minor situations if you have
a secondary vehicle which is not stuck. The
tow hooks on your vehicle are designed to
take the abusive force generated during
vehicle recovery. Do not use the bumper or
any other vehicle component as an attach -
ment point. Using tow straps requires coordi -
nation between the two drivers. Good
communication and line of sight are required
for a safe recovery. First connect the tow
strap to the correct attachment points on both vehicles. There should be a least 20 to
30 feet (6 to 9 meters) between the vehicles
to allow for a safe recovery. If necessary join
two tow straps together using a 1.5 inch hard
wood dowel. This will keep the straps from
becoming knotted and is safer than using a
clevis pin if the strap breaks. Next have the
tow vehicle backup, leaving two to three feet
worth of slack in the strap. Then the tow
vehicle, using light throttle, should accelerate
tightening the strap providing the pulling
force needed to free the vehicle. The vehicle
being recovered should assist in the
recovery, at the time of the snap, by slowly
spinning the tires in the same direction as
the pulling vehicle. After the vehicle becomes
free, the driver of the previously stuck vehicle
should signal they are free and should hit
their brakes stopping both vehicles. The
driver of the pulling vehicle should let off the
throttle without using the brakes, once
signaled by the other driver. This sequence is
important to avoid having the recovered
vehicle hit the pulling vehicle.
CAUTION!
Pulling the vehicle off an obstacle, without
first clearing the object, may result in
additional underbody damage.
CAUTION!
Damage can occur when spinning your tires
at an excessive high speed. Do not spin your
tires faster than an indicated 30 mph
(48 km/h).

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