2006 JEEP GRAND CHEROKEE wheel torque

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 prevail-
ing road conditions. ABS cannot prevent accidents,
including 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 and
stability. 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.
132 UNDERSTANDING THE FEATURES OF YOUR VEHICLE

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“Electronic
Brake Control System”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 transmissionselector in N (Neutral) for at least one minute after every
five rocking-motion cycles. This will minimize overheat-
ing and reduce the risk of transmission failure during
prolonged efforts to free a stuck vehicle.
CAUTION!
When“rocking”a stuck vehicle by moving between
“First”and R (Reverse), do not spin the wheels faster
than 15 mph (24 km/h), or drivetrain damage may
result.
STARTING AND OPERATING 261
5

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
4–wheel drive. No driver interaction is required. This
transfer case divides engine torque almost evenly with 48
percent of engine torque to the front axle and 52 percent
of engine torque to the rear axle. 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 LOW range is recommended. Refer
to“Off-Road Driving Tips”in this section.
Quadra-Trac IIOperating
Instructions/Precautions—If Equipped
The Quadra-Trac IItransfer case is fully automatic in the
normal driving 4 HI mode. The Quadra-Trac IItransfer
case provides three mode positions—four wheel drive
high range, neutral, and four wheel drive low range.
This transfer case is fully automatic in the 4 HI mode.
This transfer case divides engine torque almost evenly
with 48 percent of engine torque to the front axle and 52
percent of engine torque to the rear axle. When speed
differences are increased between the front and rear drive
shafts, the transfer case can transmit up to 100 percent of
available engine torque to the front or rear drive shafts.
When additional traction is required, the 4 LOW position
can be used to lock the front and rear driveshafts together
and force the front and rear wheels to rotate at the same
speed. The 4 LOW position is intended for loose, slippery
262 STARTING AND OPERATING

NOTE:If shift conditions/interlocks are not met, a
“CHECK SHIFT PROCEDURES”message will flash from
the EVIC (Electronic Vehicle Information Center). Refer
to“Electronic Vehicle Information Center (EVIC)”in
Section 4 of this manual. (See page 187 for more
information.)
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 func-
tion as standard axles balancing torque evenly between
left and right wheels. With a traction difference betweenleft 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.
PARKING BRAKE
To set the parking brake, pull the lever up as firmly as
possible. When the parking brake is applied with the
ignition ON, the“Brake Warning Light”in the instru-
ment cluster will light.
STARTING AND OPERATING 267
5

Traction Downhill
Shift the transmission into a low gear and the transfer
case to 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 277
5

WARNING!
Raising the vehicle higher than necessary can make
the vehicle less stable. It could slip off the jack and
hurt someone near it. Raise the vehicle only enough
to remove the tire.
6. Remove the lug nuts and wheel.
7. Position the spare wheel/tire on the vehicle and install
the lug nuts with the cone-shaped end toward the wheel.
Lightly tighten the nuts. To avoid the risk of forcing the
vehicle off the jack, do not tighten the nuts fully until the
vehicle has been lowered.
8. Lower the vehicle by turning the jack screw counter
clockwise, and remove the jack and wheel blocks.9. Finish tightening the lug nuts. Push down on the
wrench while tightening for increased leverage. Alternate
nuts until each nut has been tightened twice. Correct
wheel nut tightness is 130 N·m (95 ft. lbs). 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 it’s 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.
WHAT TO DO IN EMERGENCIES 335
6

Tire Identification Number (TIN)............. 282
Tire Markings.......................... 279
Tire Safety Information.................... 279
Tires ............................70,287,421
Air Pressure.......................... 288
Alignment and Balance.................. 293
Chains.............................. 300
Changing............................ 330
General Information.................... 287
High Speed.......................... 290
Inflation Pressures..................... 288
Jacking............................. 330
Life of Tires.......................... 292
Load Capacity.....................283,284
Pressure Monitor System (TPMS)........... 294
Pressure Warning Light.................. 183
Quality Grading....................... 421
Radial.............................. 290
Replacement......................... 292Rotation............................. 301
Safety............................70,279
Sizes............................... 280
Spare Tire........................... 331
Spinning............................ 290
Tread Wear Indicators................... 291
Wheel Mounting....................... 335
Tongue Weight/Trailer Weight.............. 313
Torque Converter Clutch.................. 260
Tow Hooks, Emergency................... 338
Tow/Haul Indicator Light................. 184
Towing............................308,339
Disabled Vehicle....................... 339
Guide.............................. 312
Recreational.......................... 320
Weight.............................. 312
Traction Control......................... 132
Traction Control Light.................... 182
Trailer Towing.......................... 308
INDEX 439
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