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Select (ERS) shift control (refer to “Electronic Range
Select (ERS) Operation” in this section for further infor-
mation) to select a lower gear range. Under these condi-
tions, using a lower gear range will improve performance
and extend transmission life by reducing excessive shift-
ing and heat buildup.
If the transmission temperature exceeds normal operat-
ing limits, the powertrain controller will modify the
transmission shift schedule and expand the range of
torque converter clutch engagement. This is done to
prevent transmission 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 caution when operating a heavily loaded
vehicle 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
significant additional heat load on the cooling system.
Downshifting the transmission to the lowest possible
gear (when climbing a grade), or shifting to NEUTRAL
(when stopped in heavy traffic) can help to reduce this
excess heat generation.
During cold temperatures, transmission operation may
be modified depending on engine and transmission
temperature as well as vehicle speed. This feature im-
proves warm up time of the engine and transmission to
achieve maximum efficiency. Engagement of the torque
converter clutch is inhibited until the transmission fluid
is warm (refer to the “Note” under “Torque Converter
Clutch” in this section). On Pickup models with 68RFE
transmission, top overdrive gear is also inhibited until
the transmission fluid is warm, and during extremely
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![Ram 2500 2016 Diesel Supplement cold temperatures (-16°F [-27°C] or below), operation
may briefly be limited to first and direct gears only. On
trucks with AS69RC transmission, fifth and sixth gears
may be inhibited briefly on col Ram 2500 2016 Diesel Supplement cold temperatures (-16°F [-27°C] or below), operation
may briefly be limited to first and direct gears only. On
trucks with AS69RC transmission, fifth and sixth gears
may be inhibited briefly on col](/manual-img/34/12564/w960_12564-294.png)
cold temperatures (-16°F [-27°C] or below), operation
may briefly be limited to first and direct gears only. On
trucks with AS69RC transmission, fifth and sixth gears
may be inhibited briefly on cold starts below 41°F (5°C),
and during very cold temperatures (-4°F [-20°C] or
below), operation may briefly be limited to third gear
only. During this condition, the ability of the vehicle to
accelerate under heavily loaded conditions may be re-
duced. In all cases, normal operation will resume once
the transmission temperature has risen to a suitable level.
Transmission Limp Home Mode
Transmission function is monitored electronically for
abnormal conditions. If a condition is detected that could
result in transmission damage, Transmission Limp Home
Mode is activated. In this mode, the transmission remains
in fourth gear (for 68RFE transmission) or third gear (for
AS69RC transmission) regardless of which forward gear
is selected. If an AS69RC-equipped truck enters LimpHome Mode at highway speeds, it will initially engage
fifth gear, until the vehicle slows to a speed where third
gear can be engaged. PARK, REVERSE, and NEUTRAL
will continue to operate. The Malfunction Indicator Light
(MIL) may be illuminated. Limp Home Mode allows the
vehicle to be driven to an authorized dealer for service
without damaging the transmission.
In the event of a momentary problem, the transmission
can be reset to regain all forward gears by performing the
following steps:
1. Stop the vehicle.
2. Shift the transmission into PARK.
3. Turn the ignition switch to the OFF position.
4. Wait approximately 10 seconds.
5
STARTING AND OPERATING 293
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CAUTION!
If you skip a gear while downshifting or downshift
at too high of a vehicle speed, these conditions may
cause the engine to overspeed if too low of a gear is
selected and the clutch pedal is released. Damage to
the clutch and the transmission can result from
skipping a gear while downshifting or downshifting
at too high of a vehicle speed even if the clutch pedal
is held pressed (i.e., not released).
Reverse Shifting
To shift into REVERSE (R), bring the vehicle to a com-
plete stop. Press the clutch and pause briefly to allow the
gear train to stop rotating. Beginning from the NEUTRAL
(N) position, move the shift lever in one quick smooth
motion straight across and into the REVERSE (R) area(the driver will feel a firm “click” as the shifter passes the
“knock-over”). Complete the shift by pulling the shift
lever into REVERSE (R).
The “knock-over” prevents the driver from accidentally
entering the REVERSE (R) shift area and warns the driver
that they are about to shift the transmission into RE-
VERSE (R). Due to this feature, a slow shift to REVERSE
(R) can be perceived as a high shift effort.
To shift out of REVERSE bring the vehicle to a complete
stop and press the clutch. Shifting out of REVERSE prior
to a complete stop may cause high shift effort.AUXILIARY SWITCHES — IF EQUIPPED
There can be up to five auxiliary switches located in the
lower switch bank of the instrument panel which can be
used to power various electronic devices and PTO
(Power Take Off) – If Equipped. If Power Take Off is
equipped, it will take the place of the fifth Auxiliary
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CAUTION!
•To avoid DEF spillage, and possible damage to the
DEF tank from overfilling, do not “top off” the DEF
tank after filling.
• DO NOT OVERFILL. DEF will freeze below 12ºF
(-11ºC). The DEF system is designed to work in
temperatures below the DEF freezing point, how-
ever, if the tank is overfilled and freezes, the
system could be damaged.
• When DEF is spilled, clean the area immediately
with water and use an absorbent material to soak
up the spills on the ground.
• Do not attempt to start your engine if DEF is
accidentally added to the diesel fuel tank as it can
result in severe damage to your engine, including
but not limited to failure of the fuel pump and
injectors.
(Continued)
CAUTION! (Continued)
•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) 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.
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.
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second filter location is on the frame behind the front
axle. The best access to this water drain valve is from
under the vehicle.
CAUTION!
•Do not drain the fuel/water separator filters when
the engine is running.
• Diesel fuel will damage blacktop paving surfaces.
Drain the filters into an appropriate container.
If water is detected in the water separator while the
engine is running, or while the ignition switch is in the
ON position, the “Water In Fuel Indicator Light” will
illuminate and an audible chime will be heard five times.
At this point you should stop the engine and drain the
water from both of the filters.
CAUTION!
If the “Water In Fuel Indicator Light” remains on, DO
NOT START the engine before you drain water from
the fuel filters to avoid engine damage.
If the “Water In Fuel Indicator Light” comes on and a
single chime is heard while you are driving, or with the
ignition switch in the ON position, there may be a
problem with your water separator wiring or sensor. See
your authorized dealer for service.
Upon proper draining of the water from both fuel filters,
the “Water In Fuel Indicator Light” will remain illumi-
nated for approximately 10 seconds. If the water was
drained while the engine was running, the “Water In Fuel
Indicator Light” may remain on for approximately three
minutes.
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MAINTAINING YOUR VEHICLE 345