2021 JEEP WRANGLER UNLIMITED Owner handbook (in English)

231
Automatic Transmission
Selection Of Lubricant
It is important to use the proper transmission
fluid to ensure optimum transmission perfor-
mance and life. Use only the manufacturer's
specified transmission fluid. Refer to “Fluids
And Lubricants” in “Technical Specifica -
tions” for fluid specifications. It is important
to maintain the transmission fluid at the
correct level using the recommended fluid.
NOTE:
No chemical flushes should be used in any
transmission; only the approved lubricant
should be used.
Special Additives
The manufacturer strongly recommends
against using any special additives in the
transmission. Automatic Transmission Fluid
(ATF) is an engineered product and its
performance may be impaired by supple -
mental additives. Therefore, do not add any
fluid additives to the transmission. Avoid
using transmission sealers as they may
adversely affect seals.
To avoid contamination from foreign
matter or moisture, use only new brake
fluid or fluid that has been in a tightly
closed container. Keep the master cylinder
reservoir cap secured at all times. Brake
fluid in a open container absorbs moisture
from the air resulting in a lower boiling
point. This may cause it to boil unexpect -
edly during hard or prolonged braking,
resulting in sudden brake failure. This
could result in a collision.

Overfilling the brake fluid reservoir can
result in spilling brake fluid on hot
engine parts, causing the brake fluid to
catch fire. Brake fluid can also damage
painted and vinyl surfaces, care should
be taken to avoid its contact with these
surfaces.
Do not allow petroleum based fluid to
contaminate the brake fluid. Brake seal
components could be damaged, causing
partial or complete brake failure. This
could result in a collision.
WARNING! (Continued)
CAUTION!
Using a transmission fluid other than the
manufacturer’s recommended fluid may
cause deterioration in transmission shift
quality and/or torque converter shudder.
Refer to “Fluids And Lubricants” in
“Technical Specifications” for fluid
specifications.
CAUTION!
Do not use chemical flushes in your
transmission as the chemicals can damage
your transmission components. Such
damage is not covered by the New Vehicle
Limited Warranty.
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SERVICING AND MAINTENANCE
232
(Continued)
Fluid Level Check
The fluid level is preset at the factory and
does not require adjustment under normal
operating conditions. Routine fluid level
checks are not required; therefore the trans-
mission has no dipstick. An authorized
dealer can check your transmission fluid
level using special service tools. If you notice
fluid leakage or transmission malfunction,
visit an authorized dealer immediately to
have the transmission fluid level checked.
Operating the vehicle with an improper fluid
level can cause severe transmission damage.
RAISING THE VEHICLE
In the case where it is necessary to raise the
vehicle, go to an authorized dealer or service
station.
TIRES
Tires — General Information
Tire Pressure
Proper tire inflation pressure is essential to
the safe and satisfactory operation of your
vehicle. Four primary areas are affected by
improper tire pressure:
Safety
Fuel Economy
Tread Wear
Ride Comfort and Vehicle Stability
Safety Both underinflation and overinflation affect
the stability of the vehicle and can produce
a feeling of sluggish response or over respon
-
siveness in the steering.
NOTE:
Unequal tire pressures from side to side
may cause erratic and unpredictable
steering response.
Unequal tire pressure from side to side
may cause the vehicle to drift left or right.
Fuel Economy

Underinflated tires will increase tire rolling
resistance resulting in higher fuel consumption.

CAUTION!
If a transmission fluid leak occurs, visit an
authorized dealer immediately. Severe
transmission damage may occur. An
authorized dealer has the proper tools to
adjust the fluid level accurately.
WARNING!
Improperly inflated tires are dangerous
and can cause collisions.
Underinflation increases tire flexing and
can result in overheating and tire failure.
Overinflation reduces a tire's ability to
cushion shock. Objects on the road and
chuckholes can cause damage that
result in tire failure.

Overinflated or underinflated tires can affect
vehicle handling and can fail suddenly,
resulting in loss of vehicle control.

Unequal tire pressures can cause
steering problems. You could lose
control of your vehicle.
Unequal tire pressures from one side of
the vehicle to the other can cause the
vehicle to drift to the right or left.

Always drive with each tire inflated to the
recommended cold tire inflation pressure.

WARNING! (Continued)
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233
Tread Wear
Improper cold tire inflation pressures can
cause abnormal wear patterns and reduced
tread life, resulting in the need for earlier tire
replacement.
Ride Comfort And Vehicle Stability
Proper tire inflation contributes to a comfort-
able ride. Overinflation produces a jarring
and uncomfortable ride.
Tire Inflation Pressures
The proper cold tire inflation pressure is
listed on the left side B-Pillar or rear edge of
the passenger door.
Tire And Loading Information Placard This placard tells you important information
about the:
1. Number of people that can be carried in
the vehicle.
2. Tire size designed for your vehicle.
3. Cold tire inflation pressures for the front, rear, and spare tires.
At least once a month:
Check and adjust tire pressure with a good
quality pocket-type pressure gauge. Do not
make a visual judgement when deter -
mining proper inflation. Tires may look
properly inflated even when they are
under-inflated.
Inspect tires for signs of tire wear or visible
damage. Inflation pressures specified on the placard
are always “cold tire inflation pressure”.
Cold tire inflation pressure is defined as the
tire pressure after the vehicle has not been
driven for at least three hours, or driven less
than 1 mile (1.6 km) after sitting for a
minimum of three hours. The cold tire infla
-
tion pressure must not exceed the maximum
inflation pressure molded into the tire side -
wall.
Check tire pressures more often if subject to
a wide range of outdoor temperatures, as tire
pressures vary with temperature changes.
Tire pressures change by approximately 1 psi
(7 kPa) per 12°F (7°C) of air temperature
change. Keep this in mind when checking
tire pressure inside a garage, especially in
the Winter.
Example: If garage temperature = 68°F
(20°C) and the outside temperature = 32°F
(0°C) then the cold tire inflation pressure
should be increased by 3 psi (21 kPa), which
equals 1 psi (7 kPa) for every 12°F (7°C) for
this outside temperature condition.
Tire pressure may increase from 2 to 6 psi
(13 to 40 kPa) during operation. DO NOT
reduce this normal pressure build up or your
tire pressure will be too low.
CAUTION!
After inspecting or adjusting the tire
pressure, always reinstall the valve stem
cap. This will prevent moisture and dirt
from entering the valve stem, which could
damage the valve stem.
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SERVICING AND MAINTENANCE
234
Tire Pressures For High Speed Operation
The manufacturer advocates driving at safe
speeds and within posted speed limits.
Where speed limits or conditions are such
that the vehicle can be driven at high speeds,
maintaining correct tire inflation pressure is
very important. Increased tire pressure and
reduced vehicle loading may be required for
high-speed vehicle operation. Refer to an
authorized tire dealer or original equipment
vehicle dealer for recommended safe oper-
ating speeds, loading and cold tire inflation
pressures.
Radial Ply Tires
Tire Repair
If your tire becomes damaged, it may be
repaired if it meets the following criteria:
The tire has not been driven on when flat.

The damage is only on the tread section of
your tire (sidewall damage is not repairable).

The puncture is no greater than a ¼ of an
inch (6 mm).
Consult an authorized tire dealer for tire
repairs and additional information.
Damaged Run Flat tires, or Run Flat tires
that have experienced a loss of pressure
should be replaced immediately with another
Run Flat tire of identical size and service
description (Load Index and Speed Symbol).
Replace the tire pressure sensor as well as it
is not designed to be reused.
Run Flat Tires — If Equipped
Run Flat tires allow you the capability to
drive 50 miles (80 km) at 50 mph (80 km/h)
after a rapid loss of inflation pressure. This
rapid loss of inflation is referred to as the
Run Flat mode. A Run Flat mode occurs
when the tire inflation pressure is of/or below
14 psi (96 kPa). Once a Run Flat tire reaches
the run flat mode it has limited driving capa -
bilities and needs to be replaced immedi -
ately. A Run Flat tire is not repairable. When
a run flat tire is changed after driving with
underinflated tire condition, please replace
the TPM sensor as it is not designed to be
reused when driven under run flat mode 14
psi (96 kPa) condition.
NOTE:
TPM Sensor must be replaced after driving
the vehicle on a flat tire condition.
It is not recommended driving a vehicle
loaded at full capacity or to tow a trailer
while a tire is in the run flat mode.
See the tire pressure monitoring section for
more information.
WARNING!
High speed driving with your vehicle under
maximum load is dangerous. The added
strain on your tires could cause them to
fail. You could have a serious collision. Do
not drive a vehicle loaded to the maximum
capacity at continuous speeds above
75 mph (120 km/h).
WARNING!
Combining radial ply tires with other types
of tires on your vehicle will cause your
vehicle to handle poorly. The instability
could cause a collision. Always use radial
ply tires in sets of four. Never combine
them with other types of tires.
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235
Tire Spinning
When stuck in mud, sand, snow, or ice
conditions, do not spin your vehicle's wheels
above 30 mph (48 km/h) or for longer than
30 seconds continuously without stopping.
Refer to “Freeing A Stuck Vehicle” in “In
Case Of Emergency” for further information.
Tread Wear Indicators
Tread wear indicators are in the original
equipment tires to help you in determining
when your tires should be replaced.Tire Tread
These indicators are molded into the bottom
of the tread grooves. They will appear as
bands when the tread depth becomes a 1/16
of an inch (1.6 mm). When the tread is worn
to the tread wear indicators, the tire should
be replaced.
Refer to “Replacement Tires” in this section
for further information.
Life Of Tire
The service life of a tire is dependent upon
varying factors including, but not limited to:
Driving style
Tire pressure - Improper cold tire inflation
pressures can cause uneven wear patterns
to develop across the tire tread. These
abnormal wear patterns will reduce tread
life, resulting in the need for earlier tire
replacement
Distance driven
Performance tires, tires with a speed
rating of V or higher, and Summer tires
typically have a reduced tread life. Rota-
tion of these tires per the vehicle sched -
uled maintenance is highly recommended
WARNING!
Fast spinning tires can be dangerous.
Forces generated by excessive wheel
speeds may cause tire damage or failure. A
tire could explode and injure someone. Do
not spin your vehicle's wheels faster than
30 mph (48 km/h) for more than 30
seconds continuously when you are stuck,
and do not let anyone near a spinning
wheel, no matter what the speed.1 — Worn Tire
2 — New Tire
WARNING!
Tires and the spare tire should be replaced
after six years, regardless of the remaining
tread. Failure to follow this warning can
result in sudden tire failure. You could lose
control and have a collision resulting in
serious injury or death.
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(Continued)
NOTE:
Wheel Valve Stem must be replaced as well
when installing new tires due to wear and
tear in existing tires.
Keep dismounted tires in a cool, dry place
with as little exposure to light as possible.
Protect tires from contact with oil, grease,
and gasoline.
Replacement Tires
The tires on your new vehicle provide a
balance of many characteristics. They should
be inspected regularly for wear and correct
cold tire inflation pressures. The manufac-
turer strongly recommends that you use tires
equivalent to the originals in size, quality
and performance when replacement is
needed. Refer to the paragraph on “Tread
Wear Indicators” in this section. Refer to the
Tire and Loading Information placard or the
Vehicle Certification Label for the size desig -
nation of your tire. The Load Index and
Speed Symbol for your tire will be found on
the original equipment tire sidewall.
It is recommended to replace the two front
tires or two rear tires as a pair. Replacing just
one tire can seriously affect your vehicle’s handling. If you ever replace a wheel, make
sure that the wheel’s specifications match
those of the original wheels.
It is recommended you contact an authorized
tire dealer or original equipment dealer with
any questions you may have on tire specifica
-
tions or capability. Failure to use equivalent
replacement tires may adversely affect the
safety, handling, and ride of your vehicle. WARNING!
Do not use a tire, wheel size, load rating,
or speed rating other than that specified
for your vehicle. Some combinations of
unapproved tires and wheels may change
suspension dimensions and performance
characteristics, resulting in changes to
steering, handling, and braking of your
vehicle. This can cause unpredictable
handling and stress to steering and
suspension components. You could lose
control and have a collision resulting in
serious injury or death. Use only the tire
and wheel sizes with load ratings
approved for your vehicle.
Never use a tire with a smaller load index
or capacity, other than what was origi -
nally equipped on your vehicle. Using a
tire with a smaller load index could result
in tire overloading and failure. You could
lose control and have a collision.
Failure to equip your vehicle with tires
having adequate speed capability can
result in sudden tire failure and loss of
vehicle control.
CAUTION!
Replacing original tires with tires of a
different size may result in false
speedometer and odometer readings.
WARNING! (Continued)
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237
Tire Types
All Season Tires — If Equipped
All Season tires provide traction for all
seasons (Spring, Summer, Autumn, and
Winter). Traction levels may vary between
different all season tires. All season tires can
be identified by the M+S, M&S, M/S or MS
designation on the tire sidewall. Use all
season tires only in sets of four; failure to do
so may adversely affect the safety and
handling of your vehicle.

Summer Or Three Season Tires — If Equipped

Summer tires provide traction in both wet
and dry conditions, and are not intended to
be driven in snow or on ice. If your vehicle is
equipped with Summer tires, be aware these
tires are not designed for Winter or cold
driving conditions. Install Winter tires on
your vehicle when ambient temperatures are
less than 40°F (5°C) or if roads are covered
with ice or snow. For more information,
contact an authorized dealer.

Summer tires do not contain the all season desig-
nation or mountain/snowflake symbol on the tire
sidewall. Use Summer tires only in sets of four;
failure to do so may adversely affect the safety
and handling of your vehicle.

Snow Tires
Some areas of the country require the use of
snow tires during the Winter. Snow tires can
be identified by a “mountain/snowflake”
symbol on the tire sidewall.
If you need snow tires, select tires
equivalent in size and type to the
original equipment tires. Use snow
tires only in sets of four; failure to
do so may adversely affect the safety and
handling of your vehicle.
Snow tires generally have lower speed ratings
than what was originally equipped with your
vehicle and should not be operated at
sustained speeds over 75 mph (120 km/h).
For speeds above 75 mph (120 km/h) refer
to original equipment or an authorized tire
dealer for recommended safe operating
speeds, loading and cold tire inflation pres -
sures. While studded tires improve performance on
ice, skid and traction capability on wet or dry
surfaces may be poorer than that of
non-studded tires. Some states prohibit
studded tires; therefore, local laws should be
checked before using these tire types.
Spare Tires — If Equipped
NOTE:
For vehicles equipped with Tire Service Kit
instead of a spare tire, please refer to “Tire
Service Kit” in “In Case Of Emergency” in
the Owner’s Manual for further information.
Refer to the “Towing Requirements - Tires”
in “Starting And Operating” in the Owner’s
Manual for restrictions when towing with a
spare tire designated for temporary emer
-
gency use.
WARNING!
Do not use Summer tires in snow/ice
conditions. You could lose vehicle control,
resulting in severe injury or death. Driving
too fast for conditions also creates the
possibility of loss of vehicle control.
CAUTION!
Because of the reduced ground clearance,
do not take your vehicle through an
automatic car wash with a compact or
limited use temporary spare installed.
Damage to the vehicle may result.
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SERVICING AND MAINTENANCE
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Spare Tire Matching Original Equipped Tire
And Wheel — If Equipped
Your vehicle may be equipped with a spare
tire and wheel equivalent in look and func-
tion to the original equipment tire and wheel
found on the front or rear axle of your vehicle.
This spare tire may be used in the tire rota -
tion for your vehicle. If your vehicle has this
option, refer to an authorized tire dealer for
the recommended tire rotation pattern.
Compact Spare Tire — If Equipped
The compact spare is for temporary emer -
gency use only. You can identify if your
vehicle is equipped with a compact spare by
looking at the spare tire description on the
Tire and Loading Information Placard
located on the driver’s side door opening or
on the sidewall of the tire. Compact spare
tire descriptions begin with the letter “T” or
“S” preceding the size designation.
Example: T145/80D18 103M.
T, S = Temporary Spare Tire
Since this tire has limited tread life, the orig -
inal equipment tire should be repaired (or
replaced) and reinstalled on your vehicle at
the first opportunity. Do not install a wheel cover or attempt to
mount a conventional tire on the compact
spare wheel, since the wheel is designed
specifically for the compact spare tire. Do
not install more than one compact spare tire
and wheel on the vehicle at any given time.
Full Size Spare — If Equipped
The full size spare is for temporary emer
-
gency use only. This tire may look like the
originally equipped tire on the front or rear
axle of your vehicle, but it is not. This spare
tire may have limited tread life. When the
tread is worn to the tread wear indicators, the
temporary use full size spare tire needs to be
replaced. Since it is not the same as your
original equipment tire, replace (or repair)
the original equipment tire and reinstall on
the vehicle at the first opportunity.
Limited Use Spare — If Equipped
The limited use spare tire is for temporary
emergency use only. This tire is identified by
a label located on the limited use spare
wheel. This label contains the driving limita -
tions for this spare. This tire may look like
the original equipped tire on the front or rear
axle of your vehicle, but it is not. Installation
of this limited use spare tire affects vehicle
handling. Since it is not the same as your
original equipment tire, replace (or repair)
the original equipment tire and reinstall on
the vehicle at the first opportunity.
WARNING!
Compact and collapsible spares are for
temporary emergency use only. With these
spares, do not drive more than 50 mph
(80 km/h). Temporary use spares have
limited tread life. When the tread is worn
to the tread wear indicators, the temporary
use spare tire needs to be replaced. Be
sure to follow the warnings, which apply to
your spare. Failure to do so could result in
spare tire failure and loss of vehicle
control.
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