2009 JEEP GRAND CHEROKEE torque

left “D(-)” and hold it there. The transmission will shift to
the range from which the vehicle can best be slowed
down.
Overdrive Operation
The automatic transmission includes an electronically
controlled Overdrive (5th gear for 3.7L and 3.0L diesel
engine, 4th and 5th gears for 4.7L and 5.7L engines). The
transmission will automatically shift to Overdrive, if the
following conditions are present:
•the transmission selector is in DRIVE;
•the engine coolant has reached normal operating tem-
perature;
•vehicle speed is above approximately 30 mph
(48 km/h);
•the TOW/HAUL switch has not been activated;
•transmission has reached normal operating
temperature.
NOTE:If the vehicle is started in extremely cold tem-
peratures, the transmission may not shift into Overdrive
and will automatically select the most desirable gear for
operation at this temperature. Normal operation will
resume when the transmission fluid temperature has
risen to a suitable level. Refer also to the Note under
torque converter clutch, later in this section.
During cold temperature operation you may notice de-
layed upshifts, depending on engine and transmission
temperature. This feature improves the warmup time of
the engine and transmission.
If the transmission temperature gets extremely hot, the
transmission will automatically select the most desirable
gear for operation at this temperature. If the transmission
temperature becomes hot enough, the “TRANSMISSION
292 STARTING AND OPERATING

activated. Pressing the switch a second time restores
normal operation. If the TOW/HAUL mode is desired,
the switch must be pressed each time the engine is
started.
Transmission Limp Home Mode
Transmission function is monitored for abnormal condi-
tions. If a condition is detected that could result in
transmission damage, the transmission limp home mode
will be engaged. In this mode, the transmission will
remain in the current gear (3.7L and 3.0L diesel engine) or
in direct gear (4.7L and 5.7L engines) until the vehicle is
brought to a stop.
To reset the transmission, use the following procedure:
1. Stop the vehicle.
2. Move the shift lever into the PARK position.
3. Turn the engine off, and be sure to turn the key to the
LOCK position.4. Wait approximately 10 seconds, then restart the en-
gine.
5. Move the shift lever to the desired gear range.
If the problem is no longer detected, the transmission will
return to normal operation. If the problem persists,
PARK, REVERSE, and NEUTRAL will continue to oper-
ate. Only 2nd gear (3.7L and 3.0L diesel engine) or 3rd
gear (4.7L and 5.7L engines) will be available in the
DRIVE position. Have the transmission checked at your
authorized dealer as soon as possible.
Torque Converter Clutch
A feature, designed to improve fuel economy, has been
included in the automatic transmission on your vehicle.
A clutch within the torque converter engages automati-
cally, at a calibrated speed, at light throttle. It engages at
higher speeds under heavier acceleration. This may re-
sult in a slightly different feeling or response during
normal operation in high gear. When the vehicle speed
294 STARTING AND OPERATING

drops below a calibrated speed, or during acceleration,
the clutch automatically and smoothly disengages. The
feature is operational in Overdrive and in DRIVE.
NOTE:
•The torque converter clutch will not engage until the
transmission fluid and engine coolant are warm [usu-
ally after 1 to 3 miles (1.6 to 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. For vehicles
with 4.7L or 5.7L engines (which have two Overdrive
gears), the transmission may not shift into the top
Overdrive gear (normal 5th gear) until the transmis-
sion fluid and engine coolant are warm.
•If the vehicle has not been driven in several days, the
first few seconds of operation after shifting the trans-
mission 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 con-
verter 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 shift lever
between DRIVE and 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 “Electronic
Brake Control System” in Section 3 of this manual.
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5

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 shift lever in
NEUTRAL for at least one minute after every five
rocking-motion cycles. This will minimize overheating
and reduce the risk of transmission failure during pro-
longed efforts to free a stuck vehicle.
CAUTION!
When “rocking” a stuck vehicle by moving between
“First” and REVERSE, do not spin the wheels faster
than 15 mph (24 km/h), or drivetrain damage may
result.
FOUR-WHEEL DRIVE OPERATION
Quadra-Trac IOperating
Instructions/Precautions — If Equipped
The Quadra-Trac Iis a single-speed (HI range only)
transfer case, which provides convenient full-time four–
wheel drive. No driver interaction is required. The Brake
Traction Control System (BTC), which combines standard
ABS and Traction Control, provides resistance to any
wheel that is slipping to allow additional torque transfer
to wheels with traction.
NOTE:The Quadra-Trac Isystem is not appropriate
for conditions where 4WD LOW range is recommended.
Refer to “Off-Road Driving Tips” in this section.
296 STARTING AND OPERATING

Quadra-Drive IISystem — If Equipped
The optional Quadra-Drive IISystem features three
torque transfer couplings. The couplings include ELSD
(Electronic Limited-Slip Differential) front and rear axles
and Quadra-Trac IItransfer case. The optional ELSD
axles are fully automatic and require no driver input to
operate. Under normal driving conditions, the units
function as standard axles, balancing torque evenly be-
tween left and right wheels. With a traction difference
between left and right wheels, the coupling will sense a
speed difference. As one wheel begins to spin faster than
the other, torque will automatically transfer from the
wheel that has less traction, to the wheel that has traction.
While the transfer case and axle couplings differ in
design, their operation is similar. Follow the Quadra-Trac
IItransfer case shifting information, preceding this
section, for shifting this system.
ON-ROAD DRIVING TIPS
Utility vehicles have higher ground clearance and a
narrower track to make them capable of performing in a
wide variety of off-road applications. Specific design
characteristics give them a higher center of gravity than
ordinary cars.
An advantage of the higher ground clearance is a better
view of the road, allowing you to anticipate problems.
They are not designed for cornering at the same speeds as
conventional two-wheel drive vehicles any more than
low-slung sports cars are designed to perform satisfacto-
rily in off-road conditions. If at all possible, avoid sharp
turns or abrupt maneuvers. As with other vehicles of this
type, failure to operate this vehicle correctly may result in
loss of control or vehicle rollover.
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5

Traction Downhill
Shift the transmission into a low gear, and the transfer
case into 4WD LOW range. Let the vehicle go slowly
down the hill with all four wheels turning against engine
compression drag. This will permit you to control the
vehicle speed and direction.
When descending mountains or hills, repeated braking
can cause brake fade with loss of braking control. Avoid
repeated heavy braking by downshifting the transmis-
sion whenever possible.
After Driving Off-Road
Off-road operation puts more stress on your vehicle than
does most on-road driving. After going off-road, it is
always a good idea to check for damage. That way you
can get any problems taken care of right away and have
your vehicle ready when you need it.
•Completely inspect the underbody of your vehicle.
Check tires, body structure, steering, suspension, and
exhaust system for damage.
•Check threaded fasteners for looseness, particularly on
the chassis, drivetrain components, steering, and sus-
pension. Retighten them, if required, and torque to the
values specified in the Service Manual.
•Check for accumulations of plants or brush. These
things could be a fire hazard. They might hide damage
to fuel lines, brake hoses, axle pinion seals, and
propeller shafts.
•After extended operation in mud, sand, water, or
similar dirty conditions, have brake rotors, wheels,
brake linings, and axle yokes inspected and cleaned as
soon as possible.
STARTING AND OPERATING 305
5

WARNING!
ABS (Anti-Lock Brake System) cannot prevent the
natural laws of physics from acting on the vehicle,
nor can it increase the traction afforded by prevailing
road conditions. ABS cannot prevent accidents, in-
cluding those resulting from excessive speed in
turns, driving on very slippery surfaces, or hydro-
planing. Only a safe, attentive, and skillful driver can
prevent accidents. The capabilities of an ABS-
equipped vehicle must never be exploited in a reck-
less or dangerous manner which could jeopardize the
user’s safety or the safety of others.
TCS (Traction Control System)
This system monitors the amount of wheel spin of each of
the driven wheels. If wheel spin is detected, brake
pressure is applied to the slipping wheel(s) and engine
power is reduced to provide enhanced acceleration andstability. A feature of the TCS system functions similar to
a limited-slip differential and controls the wheel spin
across a driven axle. If one wheel on a driven axle is
spinning faster than the other, the system will apply the
brake of the spinning wheel. This will allow more engine
torque to be applied to the wheel that is not spinning.
This feature remains active even if TCS and ESP are in
either the “Partial Off” or “Full Off” modes. Refer to “ESP
(Electronic Stability Program)” in this section for more
information.
BAS (Brake Assist System)
The BAS is designed to optimize the vehicle’s braking
capability during emergency braking maneuvers. The
system detects an emergency braking situation by sens-
ing the rate and amount of brake application and then
applies optimum pressure to the brakes. This can help
reduce braking distances. The BAS complements the
anti-lock brake system (ABS). Applying the brakes very
quickly results in the best BAS assistance. To receive the
STARTING AND OPERATING 313
5

wheel nut tightness is 95 ft lbs (130 N·m). If in doubt
about the correct tightness, have them checked with a
torque wrench by your authorized dealer or at a service
station.
10. Lower the jack to its fully closed position.
WARNING!
A loose tire or jack, thrown forward in a collision or
hard stop could endanger the occupants of the ve-
hicle. Always stow the jack parts and the spare tire in
the places provided.
11. Secure the tire, jack, and tools in their proper loca-
tions.
NOTE:A tire should be stowed with the “beauty” side
up. Storing the tire upside down may result in scratching
or damage to the wheel face. Continue winching up the
tire until you hear the winch “ratchet” three times.Double check to ensure the tire is snug against the
underbody of the vehicle. Damage to the winch cable
may result if the vehicle is driven with the tire loose.
WARNING!
Do not use power tools to winch the tire up or down.
Impact-type tools may damage the winch mecha-
nism.
12. Reinstall the plastic plug into the floor of the cargo
area.
JUMP-STARTING
If the vehicle has a discharged battery, booster cables may
be used to obtain a start from a booster battery or the
battery in another vehicle. This type of start can be
dangerous if done improperly, so follow this procedure
carefully.
398 WHAT TO DO IN EMERGENCIES