2018 Ram 2500 cooling

Electronic Range Select (ERS) Operation —
Six-Speed Transmission (1500 Models Only)
The Electronic Range Select (ERS) shift control allows the
driver to limit the highest available gear when the trans-
mission is in DRIVE. For example, if you set the transmis-
sion gear limit to 4 (fourth gear), the transmission will not
shift above fourth gear, but will shift through the lower
gears normally.
Use of ERS (or TOW/HAUL mode) also enables an addi-
tional underdrive gear which is not normally used during
through-gear accelerations. This additional gear can im-
prove vehicle performance and cooling capability when
towing a trailer on certain grades. In ERS mode, gears 1
though 3 are underdrive gears, and ERS 4 is direct drive.
ERS 5 and 6 (Overdrive gears) are the same as the normal
fourth and fifth gears.
You can switch between DRIVE and ERS mode at any
vehicle speed. When the gear selector is in the DRIVE
position, the transmission will operate automatically, shift-
ing between all available gears. Tapping the ERS (-) switch
(column shift) or tapping the gear selector to the left (-)
(console shift) will activate ERS mode, display the currentgear in the instrument cluster, and set that gear as the top
available gear. For example, if you are in DRIVE and are in
third (direct) gear, when you tap the gear selector/switch
one time in the (-) direction, the display will show 4 (ERS
4 is direct gear). Another tap down (-) will shift the
transmission down to ERS 3 (the added underdrive gear).
Once in ERS mode, tapping (-) or (+) will change the top
available gear.
Column Gear Selector
312 STARTING AND OPERATING

WARNING!
Do not coast in NEUTRAL and never turn off the
ignition to coast down a hill. These are unsafe practices
that limit your response to changing traffic or road
conditions. You might lose control of the vehicle and
have a collision.
CAUTION!
Towing the vehicle, coasting, or driving for any other
reason with the transmission in NEUTRAL can cause
severe transmission damage. Refer to “Recreational
Towing” in “Starting And Operating” and “Towing A
Disabled Vehicle” in “In Case Of Emergency” for
further information.
DRIVE (D)
This range should be used for most city and highway
driving. It provides the smoothest upshifts and downshifts,
and the best fuel economy. The transmission automatically
upshifts through underdrive first, second, and third gears,
direct fourth gear and overdrive fifth and sixth gears. The
DRIVE position provides optimum driving characteristics
under all normal operating conditions. When frequent transmission shifting occurs (such as when
operating the vehicle under heavy loading conditions, in
hilly terrain, traveling into strong head winds, or while
towing a heavy trailer), use the Electronic Range Select
(ERS) shift control (refer to “Electronic Range Select (ERS)
Operation” in this section for further information) to select
a lower gear range. Under these conditions, using a lower
gear range will improve performance and extend transmis-
sion life by reducing excessive shifting and heat buildup.
If the transmission temperature exceeds normal operating
limits, the powertrain controller will modify the transmis-
sion shift schedule and expand the range of torque con-
verter clutch engagement. This is done to prevent trans-
mission damage due to overheating.
If the transmission becomes extremely hot or is in danger
of overheating, the “Transmission Temperature Warning
Light” may illuminate and the transmission may operate
differently until the transmission cools down.
NOTE:
Use cautionwhen operating a heavily loaded ve-
hicle at low speeds (such as towing a trailer up a steep
grade, or in stop-and-go traffic) during hot weather. In
these conditions, torque converter slip can impose a sig-
nificant additional heat load on the cooling system. Down-
shifting the transmission to the lowest possible gear (when
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STARTING AND OPERATING 319

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.
CAUTION!
Muddy waters can reduce the cooling system effective-
ness by depositing debris onto the radiator.
• Crossing Ditches, Streams, Shallow Rivers Or Other
Flowing Water – Flowing water can be extremely dan-
gerous. 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 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 determine
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.
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.
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 sur-
faces 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 so,
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STARTING AND OPERATING 371

frequent trailer towing.Refer to the “Maintenance Plan”
for the proper maintenance intervals.
NOTE: Check the automatic transmission fluid level be-
fore towing (6-speed automatic only).
Tow/Haul Mode
To reduce potential for automatic transmission overheat-
ing, activate TOW/HAUL mode when driving in hilly
areas, or select a lower gear range (using the Electronic
Range Select (ERS) shift control) on more severe grades.
Speed Control — If Equipped
• Do not use on hilly terrain or with heavy loads.
• When using the speed control, if you experience speed
drops greater than 10 mph (16 km/h), disengage until
you can get back to cruising speed.
• Use speed control in flat terrain and with light loads to
maximize fuel efficiency.
Cooling System
To reduce potential for engine and transmission overheat-
ing, take the following actions:
•City Driving
• In city traffic — while stopped, place the transmission in
NEUTRAL, but do not increase engine idle speed.
• Highway Driving
• Reduce speed.
• Air Conditioning
• Turn off temporarily.
Air Suspension System
To aid in attaching/detaching the trailer from the vehicle,
the air suspension system can be used. Refer to “Air
Suspension System” in “Starting And Operating” for fur-
ther information.
NOTE: The vehicle must remain in the engine running
position while attaching a trailer for proper leveling of the
air suspension system.
432 STARTING AND OPERATING

WARNING!
•Take care to avoid the radiator cooling fan whenever
the hood is raised. It can start anytime the ignition
switch is ON. You can be injured by moving fan
blades.
• Remove any metal jewelry such as rings, watch
bands and bracelets that could make an inadvertent
electrical contact. You could be seriously injured.
(Continued)
WARNING! (Continued)
•Batteries contain sulfuric acid that can burn your
skin or eyes and generate hydrogen gas which is
flammable and explosive. Keep open flames or
sparks away from the battery.
1. Apply the parking brake, shift the automatic transmis- sion into PARK and turn the ignition to LOCK.
2. Turn off the heater, radio, and all unnecessary electrical accessories.
3. If using another vehicle to jump start the battery, park the vehicle within the jumper cables reach, apply the
parking brake and make sure the ignition is OFF.
WARNING!
Do not allow vehicles to touch each other as this could
establish a ground connection and personal injury
could result.
Correct Positive Jumping Location
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IN CASE OF EMERGENCY 503

6. Once the engine is started, remove the jumper cables inthe reverse sequence:
Disconnecting The Jumper Cables
1. Disconnect the negative (-)end of the jumper cable from
the engine ground of the vehicle with the discharged
battery.
2. Disconnect the opposite end of the negative (-)jumper
cable from the negative (-)post of the booster battery.
3. Disconnect the positive (+)end of the jumper cable from
the positive (+)post of the booster battery.
4. Disconnect the opposite end of the positive (+)jumper
cable from the positive (+)post of the vehicle with the
discharged battery.
If frequent jump starting is required to start your vehicle
you should have the battery and charging system in-
spected at an authorized dealer.
CAUTION!
Accessories plugged into the vehicle power outlets
draw power from the vehicle’s battery, even when not
(Continued)
CAUTION! (Continued)
in use (i.e., cellular devices, etc.). Eventually, if plugged
in long enough without engine operation, the vehicle’s
battery will discharge sufficiently to degrade battery
life and/or prevent the engine from starting.
IF YOUR ENGINE OVERHEATS
In any of the following situations, you can reduce the
potential for overheating by taking the appropriate action.
•On the highways — slow down.
• In city traffic — while stopped, place the transmission in
NEUTRAL, but do not increase the engine idle speed
while preventing vehicle motion with the brakes.
NOTE: There are steps that you can take to slow down an
impending overheat condition:
• If your air conditioner (A/C) is on, turn it off. The A/C
system adds heat to the engine cooling system and
turning the A/C off can help remove this heat.
• You can also turn the temperature control to maximum
heat, the mode control to floor and the blower control to
high. This allows the heater core to act as a supplement
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IN CASE OF EMERGENCY 505

to the radiator and aids in removing heat from the
engine cooling system.
WARNING!
You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If you
see or hear steam coming from under the hood, do not
open the hood until the radiator has had time to cool.
Never try to open a cooling system pressure cap when
the radiator or coolant bottle is hot.
CAUTION!
Driving with a hot cooling system could damage your
vehicle. If the temperature gauge reads HOT (H), pull
over and stop the vehicle. Idle the vehicle with the air
conditioner turned off until the pointer drops back
into the normal range. If the pointer remains on HOT
(H), and you hear continuous chimes, turn the engine
off immediately and call for service.
GEAR SELECTOR OVERRIDE — 6-SPEED
TRANSMISSION
If a malfunction occurs and the gear selector cannot be
moved out of the PARK position, you can use one of the
following procedures to temporarily move the gear selec-
tor.
Column Gear Selector — If Equipped
1. Turn the engine OFF.
2. Firmly apply the parking brake.
3. Tilt the steering wheel to the full up position.
4. Press and maintain firm pressure on the brake pedal.
5. Insert a screwdriver or similar tool into the access port(ringed circle) on the bottom of the steering column, and
push and hold the override release lever up.
506 IN CASE OF EMERGENCY

SERVICING AND MAINTENANCE
CONTENTS
SCHEDULED SERVICING .................517
▫ Maintenance Plan ..................... .518
▫ Heavy Duty Use Of The Vehicle ............522
 ENGINE COMPARTMENT .................523
▫ 3.6L Engine ..........................523
▫ 5.7L Engine ..........................524
▫ 6.4L Engine ..........................525
▫ Checking Oil Level — Gas Engine ...........526
▫ Adding Washer Fluid ...................526
▫ Maintenance-Free Battery .................526
 DEALER SERVICE .......................527
▫ Engine Oil — Gas Engine .................528
▫ Engine Oil Filter .......................530
▫ Engine Air Cleaner Filter .................531 ▫
Air Conditioner Maintenance ..............533
▫ Front Driveshaft Lubrication — 2500/3500
(Four-Wheel Drive Models Only) ............539
▫ Accessory Drive Belt Inspection ............540
▫ Body Lubrication ..................... .541
▫ Windshield Wiper Blades .................542
▫ Exhaust System ........................545
▫ Cooling System ........................546
▫ Brake System ........................ .552
▫ Automatic Transmission ..................553
▫ Rear Axle And 4x4 Front Driving Axle Fluid
Level ...............................556
▫ Transfer Case ........................ .557
 HOISTING ............................558
 TIRES ............................... .558
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