2008 JEEP GRAND CHEROKEE heating

The transmission will downshift from Overdrive to the
most desirable gear if the accelerator pedal is fully
depressed at vehicle speeds above approximately 35 mph
(56 km/h).
When To Use ªTOW/HAULº Mode Ð If Equipped
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting oc-
curs, press the ªTOW/HAULº switch. This will improve
performance and reduce the potential for transmission
overheating or failure due to excessive shifting. When
operating in ªTOW/HAULº mode, the transmission will
shift to direct gear and Overdrive will be enabled under
steady cruise conditions.
The ªTOW/HAULº light will illuminate in the instru-
ment cluster to indicate when the switch has been
activated. Pressing the switch a second time restores
normal operation. If the ªTOW/HAULº mode is desired,
the switch must be pressed each time the engine is
started.
TOW/HAUL Switch
290 STARTING AND OPERATING

NOTE:The torque converter clutch will not engage
until the transmission fluid and engine coolant are warm
[usually after 1-3 miles (1.6 - 4.8 km) of driving]. Because
the engine speed is higher when the torque converter
clutch is not engaged, it may seem as if the transmission
is not shifting into Overdrive when cold. This is normal.
Manually shifting (using the ERS shift control) between 4
(direct gear) and 5/D (Overdrive gear) positions will
demonstrate that the transmission is able to shift into and
out of Overdrive.
NOTE:If the vehicle has not been driven in several
days, the first few seconds of operation after shifting the
transmission into gear may seem sluggish. This is due to
the fluid partially draining from the torque converter into
the transmission. This condition is normal and will not
cause damage to the transmission. The torque converter
will refill within five seconds of shifting from Park into
any other gear position.Rocking the Vehicle
If the vehicle becomes stuck in snow, sand, or mud, it can
often be moved by a rocking motion. Move the gear
selector rhythmically between D (Drive) and R (Reverse),
while applying slight pressure to the accelerator.
NOTE:The Electronic Stability Program (ESP) and
Traction Control (if equipped) should be turned OFF
before attempting to rock the vehicle. Refer to ªElectronic
Brake Control Systemº in Section 3 of this manual.
The least amount of accelerator pedal pressure to main-
tain the rocking motion without spinning the wheels or
racing the engine is most effective. Racing the engine or
spinning the wheels, due to the frustration of not freeing
the vehicle, may lead to transmission overheating and
failure. Allow the engine to idle with the transmission
selector in N (Neutral) for at least one minute after every
292 STARTING AND OPERATING

WARNING!
²Always fully apply the parking brake when leav-
ing your vehicle, or it may roll and cause damage
or injury. Also, be certain to leave the transmission
in P (Park). Failure to do so may allow the vehicle
to roll and cause damage or injury.
²Leaving children in a vehicle unattended is dan-
gerous for a number of reasons. A child or others
could be injured. Children should be warned not
to touch the parking brake or the gear selector
lever. Don't leave the keys in the ignition. A child
could operate power windows, other controls, or
move the vehicle.
²Be sure the parking brake is fully disengaged
before driving, failure to do so can lead to brake
problems due to excessive heating of the rear
brakes.When parking on a hill, turn the front wheels toward the
curb on a downhill grade and away from the curb on an
uphill grade.
The parking brake should always be applied whenever
the driver is not in the vehicle.
ANTI-LOCK BRAKE SYSTEM
The Anti-Lock Brake System (ABS) is designed to aid the
driver in maintaining vehicle control under adverse
braking conditions. The system operates with a separate
computer to modulate hydraulic pressure to prevent
wheel lock-up and help avoid skidding on slippery
surfaces.
All vehicle wheels and tires must be the same size and
type and tires must be properly inflated to produce
accurate signals for the computer.
STARTING AND OPERATING 305
5

Towing Tips Ð Automatic Transmission
The ªDº range can be selected when towing. However, if
frequent shifting occurs while in this range, the ºTow/
Haulº mode (if equipped) or a lower gear range should
be selected.
NOTE:Using the ºTow/Haulº mode (if equipped) or a
lower gear range while operating the vehicle under
heavy operating conditions will improve performance
and extend transmission life by reducing excessive shift-
ing and heat build up. This action will also provide better
engine braking.
The automatic transmission fluid and filter should be
changed if you REGULARLY tow a trailer for more than
45 minutes of continuous operation. Refer to the ªMain-
tenance Scheduleº in Section 8 of this manual for trans-
mission fluid change intervals.
NOTE:Check the automatic transmission fluid level
before towing.
Towing Tips Ð Electronic Speed Control (If
Equipped)
þ
Don't use in hilly terrain or with heavy loads.
þWhen 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.
þUse speed control in flat terrain and with light loads to
maximize fuel efficiency.
Towing Tips Ð Cooling System
To reduce potential for engine and transmission over-
heating, take the following actions:
þCity Driving
When stopped for short periods of time, put transmission
in N (Neutral) and increase engine idle speed.
þHighway Driving
Reduce speed.
STARTING AND OPERATING 363
5

IF YOUR ENGINE OVERHEATS
In any of the following situations, you can reduce the
potential for overheating by taking the appropriate ac-
tion.
²On the highways Ð Slow down.
²In city traffic Ð While stopped, put transmission in N
(Neutral), but do not increase engine idle speed.
NOTE:There are steps that you can take to slow down
an impending overheat condition. If your air conditioner
is on, turn it off. The air conditioning system adds heat to
the engine cooling system and turning off the A/C
removes this heat. You can also turn the Temperature
Control to maximum heat, the Mode Control to floor, and
the Fan Control to High. This allows the heater core to act
as a supplement to the radiator and aids in removing heat
from the engine cooling system.
CAUTION!
Driving with a hot cooling system could damage
your vehicle. If the temperature gauge reads ªHº,
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
the ªHº, and you hear continuous chimes, turn the
engine off immediately, and call for service.
WHAT TO DO IN EMERGENCIES 371
6

NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
WARNING!
A hot exhaust system can start a fire if you park over
materials that can burn. Such materials might be
grass or leaves coming into contact with your exhaust
system. Do not park or operate your vehicle in areas
where your exhaust system can contact anything that
can burn.
In unusual situations involving grossly malfunctioning
engine operation, a scorching odor may suggest severe
and abnormal catalyst overheating. If this occurs, stop
the vehicle, turn off the engine and allow it to cool.
Service, including a tune up to manufacturer's specifica-
tions, should be obtained immediately.
To minimize the possibility of catalytic converter damage:
²Do not shut off the engine or interrupt the ignition
when the transmission is in gear and the vehicle is in
motion.
²Do not try to start the engine by pushing or towing the
vehicle.
²Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing, or for prolonged periods during very rough
idle or malfunctioning operating conditions.
Crankcase Emission Control System
Proper operation of this system depends on freedom
from sticking or plugging due to deposits. As vehicle
mileage builds up, the PCV valve and passages may
accumulate deposits. If a valve is not working properly,
replace it with a new valve. DO NOT ATTEMPT TO
CLEAN THE OLD PCV VALVE!
400 MAINTAINING YOUR VEHICLE

Oil Selection.......................395,440
Oil Synthetic......................... 397
Overheating.......................... 371
Starting............................. 275
Temperature Gauge..................... 192
Engine Oil Viscosity...................... 396
Engine Oil Viscosity Chart................. 396
Enhanced Accident Response Feature.......... 54
Entry System, Illuminated.................. 21
Event Data Recorder...................... 56
Exhaust Gas Caution................69,340,407
Exhaust System......................... 406
Exterior Finish Care...................... 422
Fabric Care............................ 423
Filters
Air Cleaner.......................... 398
Engine Oil........................... 397
Engine Oil Disposal.................... 397Finish Care............................ 422
Flashers.............................. 370
Hazard Warning....................... 370
Turn Signal.....................188,437,438
Flexible Fuel Vehicles
Cruising Range........................ 343
Engine Oil........................... 343
Fuel Requirements..................340,342
Replacement Parts..................... 343
Starting............................. 343
Flipper Glass, Liftgate..................... 35
Flooded Engine Starting................... 277
Fluid Capacities......................... 440
Fluid Leaks............................. 70
Fluid Level Checks
Automatic Transmission............417,418,419
Brake............................... 414
Engine Oil........................... 394
Power Steering........................ 403
INDEX 475
10

Identification Logo..................... 395
Materials Added to..................... 397
Pressure Warning Light.................. 190
Recommendation...................395,440
Synthetic............................ 397
Viscosity..........................396,440
Onboard Diagnostic System..............390,391
Opener, Garage Door (HomeLinkt) ........... 158
Outside Rearview Mirrors.................. 78
Overdrive............................. 288
Overdrive OFF Switch.................... 288
Overhead Console....................... 157
Overheating, Engine...................193,371
Owner's Manual (Operator Manual).......... 464
Paint Care............................. 421
Paint Damage.......................... 421
Panic Alarm............................ 24
Park Sense System, Rear................... 152Parking Brake.......................... 304
Passing Light........................... 128
Pedals, Adjustable....................... 134
Personal Settings........................ 206
Pets.................................. 67
Pets, Transporting........................ 67
Phone, Cellular.......................... 81
Phone, Hands-Free (UConnectŸ)............. 81
Placard, Tire and Loading Information......... 314
Polishing and Waxing..................... 422
Port
Universal Serial Bus (USB)................ 241
USB ................................ 241
Power
Distribution Center (Fuses)............... 429
Door Locks........................... 28
Inverter............................. 169
Mirrors.............................. 79
Outlet (Auxiliary Electrical Outlet).......... 168
482 INDEX