2007 SUBARU IMPREZA differential

7-14Starting and operating
!Center differential control dial and
indicator light
The control dial is located beside the
parking brake lever. By turning the control
dial forward and rearward, it is possible to
change the initial LSD torque.
The center differential indicator lights in
the combination meter give six levels of
indication. The indicator lights and control
dial are linked; when the dial is turned to
change the initial LSD torque, the illumi-
nation position of the indicator lights
changes accordingly.
Turn the dial forward to increase the initial
LSD torque; when the white line on the
dial reaches the frontmost position, the
initial LSD torque setting is maximum. The
center differential will then be almost
completely locked and the “LOCK ”indica-
tor light will come on.Turn the dial rearward to reduce the initial
LSD torque; when the white line reaches
the rearmost position, the initial LSD
torque will be minimum and the “
”
indicator light will come on. Under this
condition, only the Mechanical LSD torque
will limit the differential action.
CAUTION
. Do not turn the control dial when
a wheel slippage occurs. Wait
until the wheelspin has been
brought under control.
. Under any of the following con-
ditions, turn the center differen-
tial control dial to the rearmost
position to minimize the initial
LSD torque:

.When a temporary spare tire is
installed
. When your vehicle is towed
. When the vehicle is stopped
with the manual mode se- lected
NOTE . A higher initial LSD torque setting
gives the vehicle greater traction when
driving straight ahead but makes cor-
nering more difficult. Remember this
when adjusting the initial LSD torque.
In general, higher initial LSD torque
settings assist driving on slippery
roads and lower settings for non-slip-
pery roads. If you become stuck in
snow or mud, turning the center differ-
ential control dial to the frontmost
position will help move the vehicle
out. (The “LOCK ”indicator will come
on at the frontmost position.). During cornering or when making
turns (especially when getting into the
garage), the rotational difference be-
tween the front and rear wheels may
cause a braking effect accompanied by
vibration and noise. This does not
indicate a problem. The phenomenon
will disappear when you turn the center
differential control dial to the rearmost position (minimum initial LSD torqueposition).
In the auto mode, it controls the initial
LSD torque automatically. While in the
auto mode, this phenomenon some-
times occurs depending on the driving
condition, however, it does not indicate
a problem..
Use the center differential indicator
light only as a rough indication of the
initial LSD torque.. If you operate the center differential
control dial while quickly accelerating
or turning a tight corner, you may feel
slight shocks. This is due to differential
action by the center differential and
does not indicate a problem.
& Temporary release
When the driver stops the vehicle and
pulls the parking brake lever after manu-
ally setting the initial LSD torque, the LSD
torque is temporarily minimized. However
the indicator in the combination meter
continues to show the driver ’s selected
initial LSD torque. When the driver re-
leases the parking brake lever, the initial
LSD torque set by the driver is restored. Automatic transmission
The automatic transmission is electroni-
cally controlled and provides 4 forward
speeds and 1 reverse speed. NOTE .
When the engine coolant tempera-
ture is still low, your vehicle ’s auto-
matic transmission will up-shift at high-
er engine speeds than when the cool-
ant temperature is sufficiently high in
order to shorten the warm-up time and
improve driveability. The gearshift tim-
ing will automatically shift to the nor-
mal timing after the engine has warmedup. . Immediately after ATF (automatic
transmission fluid) is replaced, you
may feel that the automatic transmis-
sion operation is somewhat unusual.
This results from invalidation of data
the on-board computer has collected
and stored in memory to allow the
transmission to shift at the most appro-
priate times for the current condition of
your vehicle. Optimized shifting will be
restored as the vehicle continues to be
driven for a while. Starting and operating
7-15
– CONTINUED –

7-20Starting and operating
Limited slip differential (LSD)
(if equipped)
The LSD provides optimum distribution of
power according to the difference in
revolutions between the right and left
wheels that may be caused by certain
driving conditions, thereby improving driv-
ing stability on snow-covered, muddy or
other slippery roads or when high speeddriving.
CAUTION
. Never start the engine while a tire
on one side is jacked up, as the
vehicle may move.
. If one tire is spinning in mud,
avoid continued spinning at high
speed as this could adversely
affect the LSD.
. If you use a temporary spare tire
to replace a flat tire, be sure to
use the original temporary spare
tire stored in the vehicle. Using
other sizes will adversely affect
the LSD. Power steering
The power steering system operates only
when the engine is running.
If you lose power steering assist because
the engine stops or the system fails to
function, you can steer but it will take
much more effort. NOTE
Right after the engine has been started
and before it has warmed up, you may
hear a noise coming from areas adja-
cent to the power steering pump which
is located at the right-front area of the
engine compartment. This noise is
normal. It does not indicate power
steering system trouble.
CAUTION
Do not hold the steering wheel at the
fully locked position left or right for
more than 5 seconds. This may
damage the power steering pump. Braking &
Braking tips
WARNING
Never rest your foot on the brake
pedal while driving. This can cause
dangerous overheating of the
brakes and needless wear on the
brake pads and linings.
! When the brakes get wet
When driving in rain or after washing the
vehicle, the brakes may get wet. As a
result, brake stopping distance will be
longer. To dry the brakes, drive the vehicle
at a safe speed while lightly depressing
the brake pedal to heat up the brakes. ! Use of engine braking
Remember to make use of engine braking
in addition to foot braking. When descend-
ing a grade, if only the foot brake is used,
the brakes may start working improperly
because of brake fluid overheating,
caused by overheated brake pads. To
help prevent this, shift into a lower gear to
get stronger engine braking.

8-20Driving tips
Trailer towing
Your vehicle is designed and intended to
be used primarily as a passenger-carrying
vehicle. Towing a trailer puts additional
loads on your vehicle ’s engine, drivetrain,
brakes, tires and suspension and has an
adverse effect on fuel economy.
If you do decide to tow a trailer, your safety
and satisfaction depend upon proper use
of correct equipment and cautious opera-
tion of your vehicle. Seek the advice of
your SUBARU dealer to assist you in
purchasing a hitch and other necessary
towing equipment appropriate for your
vehicle. In addition, be sure to follow the
instructions on correct installation and use
provided by the trailer and other towing
equipment manufacturers.
SUBARU assumes no responsibility for
injuries or vehicle damage that result from
trailer towing equipment, or from any
errors or omissions in the instructions
accompanying such equipment or for your
failure to follow the proper instructions.
& Warranties and maintenance
SUBARU warranties do not apply to
vehicle damage or malfunction caused
by trailer towing. If you use your vehicle to
tow a trailer, more frequent maintenance
will be required due to the additional load. (Refer to
“Maintenance schedule under
severe driving conditions ”in the “Warranty
and Maintenance Booklet ”.)
Under no circumstances should a trailer
be towed with a new vehicle or a vehicle
with any new powertrain component (en-
gine, transmission, differential, wheel
bearings, etc.) for the first 1,000 miles
(1,600 km) of driving.
& Maximum load limits
WARNING
Never exceed the maximum load
limits explained in the following.
Exceeding the maximum load limits
could cause personal injury and/or
vehicle damage.
CAUTION
. Adequate size trailer brakes are
required when the trailer and its
cargo exceed 1,000 lbs (453 kg)
total weight.
. Before towing a trailer, check the
trailer total weight, GVW, GAWs
and tongue load. Make sure the
load and its distribution in your
vehicle and trailer are accepta- ble.
! Total trailer weight
Total trailer weight
The total trailer weight (trailer weight plus
its cargo load) must never exceed the
maximum weight shown in the followingtable.

Engine overheating
WARNING
Never attempt to remove the radia-
tor cap until the engine has been
shut off and has fully cooled down.
When the engine is hot, the coolant
is under pressure. Removing the
cap while the engine is still hot
could release a spray of boiling hot
coolant, which could burn you very
seriously.
If the engine overheats, safely pull off the
road and stop the vehicle in a safe place. & If steam is coming from the
engine compartment
Turn off the engine and get everyone
away from the vehicle until it cools down. & If no steam is coming from
the engine compartment
1. Keep the engine running at idling speed.
2. Open the hood to ventilate the engine compartment.
Confirm that the cooling fan is turning. If
the fan is not turning, immediately turn off the engine and contact your authorized
dealer for repair.
3. After the engine coolant temperature
has dropped, turn off the engine.
If the temperature gauge stays at the
overheated zone, turn off the engine.
4. After the engine has fully cooled down,
check the coolant level in the reservetank.
If the coolant level is below the
“LOW ”
mark, add coolant up to the “FULL ”mark.
5. If there is no coolant in the reserve
tank, add coolant to the reserve tank.
Then remove the radiator cap and fill the
radiator with coolant.
If you remove the radiator cap from a hot
radiator, first wrap a thick cloth around the
radiator cap, then turn the cap counter-
clockwise slowly without pressing down
until it stops. Release the pressure from
the radiator. After the pressure has been
fully released, remove the cap by pressing
down and turning it. Towing
If towing is necessary, it is best done by
your SUBARU dealer or a commercial
towing service. Observe the following
procedures for safety.
WARNING
Never tow AWD vehicles (both AT
and MT) with the front wheels raised
off the ground while the rear wheels
are on the ground, or with the rear
wheels raised off the ground while
the front wheels are on the ground.
This will cause the vehicle to spin
away due to the operation or dete-
rioration of the center differential. In case of emergency
9-11
– CONTINUED –

Maintenance schedule....................................... 11-3
Maintenance precautions ................................... 11-3
Before checking or servicing in the engine compartment .................................................... 11-4
When you do checking or servicing in the engine compartment while the engine is running .......... 11-4
Engine hood ....................................................... 11-4
Engine compartment overview .......................... 11-6
Non-turbo models .............................................. 11-6
Turbo models ..................................................... 11-7
Engine oil ............................................................ 11-8
Checking the oil level ......................................... 11-8
Changing the oil and oil filter .............................. 11-9
Recommended grade and viscosity .................. 11-11
Recommended grade and viscosity under severe driving conditions .......................................... 11-12
Synthetic oil ..................................................... 11-12
Cooling system ................................................ 11-12
Cooling fan, hose and connections ................... 11-12
Engine coolant ................................................. 11-13
Air cleaner element .......................................... 11-15
Replacing the air cleaner element ..................... 11-15
Spark plugs ...................................................... 11-17
Recommended spark plugs .............................. 11-18
Drive belts ........................................................ 11-18
Manual transmission oil .................................. 11-19
Checking the oil level ....................................... 11-19
Recommended grade and viscosity .................. 11-20
Automatic transmission fluid .......................... 11-20
Checking the fluid level .................................... 11-20 Recommended fluid
......................................... 11-21
Front differential gear oil (AT vehicles) .......... 11-21
Checking the oil level ...................................... 11-21
Recommended grade and viscosity .................. 11-22
Rear differential gear oil .................................. 11-22
Checking the gear oil level ............................... 11-22
Recommended grade and viscosity .................. 11-23
Power steering fluid ........................................ 11-24
Checking the fluid level .................................... 11-24
Recommended fluid ......................................... 11-25
Brake fluid ........................................................ 11-25
Checking the fluid level .................................... 11-25
Recommended brake fluid ............................... 11-26
Clutch fluid (MT vehicles) ............................... 11-26
Checking the fluid level .................................... 11-26
Recommended clutch fluid ............................... 11-27
Brake booster .................................................. 11-27
Brake pedal ...................................................... 11-27
Checking the brake pedal free play .................. 11-27
Checking the brake pedal reserve distance....... 11-28
Clutch pedal (MT vehicles) .............................. 11-28
Checking the clutch function ............................ 11-28
Checking the clutch pedal free play .................. 11-28
Replacement of brake pad and lining ............ 11-29
Breaking-in of new brake pads and linings ....... 11-29
Parking brake stroke ....................................... 11-30
Tires and wheels .............................................. 11-30
Types of tires ................................................... 11-30
Tire inspection ................................................. 11-30
Tire pressures and wear .................................. 11-31
Maintenance and service
11

11-6Maintenance and service
Engine compartment overview &Non-turbo models1) Air cleaner element (page 11-15)
2) Manual transmission oil level gauge (MT)
(page 11-19) or Differential gear oil level
gauge (AT) (page 11-21)
3) Clutch fluid reservoir (page 11-26)
4) Automatic transmission fluid level gauge (page 11-20)
5) Brake fluid reservoir (page 11-25)
6) Fuse box (page 11-42)
7) Battery (page 11-41)
8) Windshield washer tank (page 11-36)
9) Engine coolant reservoir (page 11-13)
10) Engine oil level gauge (page 11-8)
11) Engine oil filler cap (page 11-8)
12) Radiator cap (page 11-13)
13) Power steering fluid reservoir (page 11- 24)

&Turbo models1) Air cleaner element (page 11-15)
2) Manual transmission oil level gauge (MT)
(page 11-19) or Differential gear oil level
gauge (AT) (page 11-21)
3) Automatic transmission fluid level gauge (page 11-20)
4) Clutch fluid reservoir (page 11-26)
5) Brake fluid reservoir (page 11-25)
6) Fuse box (page 11-42)
7) Battery (page 11-41)
8) Windshield washer tank (page 11-36)
9) Engine oil filler cap (page 11-8)
10) Engine coolant reservoir (page 11-13)
11) Engine oil level gauge (page 11-8)
12) Radiator cap (page 11-13)
13) Power steering fluid reservoir (page 11- 24)Maintenance and service
11-7