2005 SUBARU IMPREZA differential

7-21
Starting and operating
– CONTINUED –
mode.
NOTE yIf the differential-limiting factor is large during
cornering maneuvers, a small speed difference
between the front and rear wheels may cause tight
corner braking (a phenomenon accompanied by
vibration and noise). This phenomenon does not
indicate a problem. It will disappear if the differen-
tial-action limiting factor is reduced.y Use the center-differential indicator light only as
a rough indication of the differential-action limit-
ing factor.y If you rapidly depress and release the accelera-
tor pedal while driving at low speed, you may hear
a knocking sound from the vicinity of the center
differential and rear differential. This sound oc-
curs because of the structure of the center differ-
ential. It does not indicate a problem. „ Temporary release
When the driver stop the vehicle and pulls the parking-
brake lever after manually setting the differential-ac-
tion limiting factor, the factor is temporarily minimized.
The indicator in the combination meter continues to
show the driver’s selected differential-action limiting factor. When the driver releases the parking-brake le-
ver, the factor set by the driver is restored.

7-28
Starting and operating
4. Insert the screwdriver into the hole.
5. Push down on the screwdriver and move the selec-
tor lever from the “P” to the “N” position.
6. Remove the screwdriver from the hole. Depress
the brake pedal and start the engine.
Take your vehicle to the nearest SUBARU dealer im-
mediately to have the system repaired.
Limited slip differential (LSD) (if
equipped)
The LSD provides optimum distribution of power ac-
cording to the difference in revolutions between the
right and left wheels that may be caused by certain
driving conditions, thereby improving driving stability
on snow-covered, muddy or other slippery roads or
when high speed driving.
NOTE (WRX-STi)
The rear differential may emit a knocking sound
when the vehicle is driven slowly with the steering wheel turned fully to either side. This sound oc-
curs because of the design of the mechanical LSD.
It does not indicate a problem.
y
Never start the engine while a tire on one side
is jacked up, as the vehicle may move. y If one tire is spinning in mud, avoid continued
spinning at high speed as this could adversely
affect the LSD. y 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 siz-
HS7011BA

8-29
Driving tips
– CONTINUED –
Trailer towing
Your vehicle is designed and intended to be used pri-
marily as a passenger-carrying vehicle. Towing a trail-
er puts additional loads on your vehicle’s engine, driv-
etrain, brakes, tires and suspension and has an ad-
verse effect on fuel economy.
If you do decide to tow a trailer, your safety and satis-
faction depend upon proper use of correct equipment
and cautious operation of your vehicle. Seek the ad-
vice of your SUBARU dealer to assist you in purchas-
ing a hitch and other necessary towing equipment ap-
propriate for your vehicle. In addition, be sure to follow
the instructions on correct installation and use provid-
ed by the trailer and other towing equipment manufac-
turers.
SUBARU assumes no responsibility for injuries or ve-
hicle damage that result from trailer towing equipment,
or from any errors or omissions in the instructions ac-
companying such equipment or for your failure to fol-
low 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 “Main- tenance 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 (engine, transmission, differential, wheel
bearings, etc.) for the first 1,000 miles (1,600 km) of
driving. „
Maximum load limits
Never exceed the maximum load limits ex-
plained below. Exceeding the maximum load
limits could cause personal injury and/or vehi-
cle damage.
yAdequate size trailer brakes are required
when the trailer and its cargo exceed 1,000 lbs
(453 kg) total weight. y Before towing a trailer, check the trailer total
weight, GVW, GAWs and tongue load. Make
sure the load and its distribution in your vehicle

9-18
In case of emergency
terioration of the center differential.
„ Towing and tie-down hooks
The towing hooks should be used only in an emergen-
cy (e.g., to free a stuck vehicle from mud, sand or
snow).
Front towing hook:
1. Take out the towing hook, screwdriver and wheel
nut wrench from the on board tool bag.
2. Insert a flat-head screwdriver into the slot at point A
on the front passenger side fog light cover, then use it
to pry the cover upward. The tabs at point A on the fog light cover will come free of the bumper.
3. Pull the entire fog light cover toward you.
4. Screw the towing hook into the threaded hole until
its thread becomes invisible.
5. Tighten the towing hook securely using the wheel
nut wrench.
After towing, remove the towing hook from the vehicle
and stow it in the tool bag.
Fit the fog light cover on the bumper.
y
Do not use the towing hook except when tow-
ing your vehicle.
A
UG9030BB
UG9526BA

9-21
In case of emergency
– CONTINUED –
„Towing with all wheels on the ground
1. Check the transmission and differential oil levels
and add oil to bring it to the upper level if necessary.
2. Release the parking brake and put the transmis-
sion in neutral.
3. The ignition switch should be in the “ACC” position
while the vehicle is being towed.
4. Take up slack in the towline slowly to prevent dam-
age to the vehicle.
y Never turn the ignition switch to the “LOCK”
position while the vehicle is being towed be- cause the steering wheel and the direction of
the wheels will be locked.y
Remember that the brake booster and power
steering do not function when the engine is not
running. Because the engine is turned off, it will
take greater effort to operate the brake pedal
and steering wheel.
y If transmission failure occurs, transport your
vehicle on a flat-bed track. y Do not run the engine while being towed us-
ing this method. Transmission damage could
result if the vehicle is towed with the engine
running. y For vehicles with automatic transmission,
the traveling speed must be limited to less than
20 mph (30 km/h) and the traveling distance to
less than 31 miles (50 km). For greater speeds
and distances, transport your vehicle on a flat-
bed track.
HG9024AA

11 - 1
11
Maintenance and service
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 ............................................................ 11-5
Engine hood .................................................. 11-5
Engine compartment overview ................... 11-8 2.5-liter non-turbo models ................................ 11-8
2.0-liter turbo models ....................................... 11-9
2.5-liter turbo models ....................................... 11-10
Engine oil ...................................................... 11-11 Checking the oil level ....................................... 11-11
Changing the oil and oil filter .......................... 11-12
Recommended grade and viscosity ................ 11-16
Recommended grade and viscosity under severe driving conditions .............................. 11-18
Synthetic oil ....................................................... 11-18
Cooling system ............................................. 11-18 Cooling fan, hose and connections ................ 11-19
Engine coolant .................................................. 11-19
Air cleaner element ...................................... 11-24 Replacing the air cleaner element ................... 11-24
Spark plugs ................................................... 11-28 Recommended spark plugs ............................. 11-28
Drive belts ..................................................... 11-29
Manual transmission oil ............................... 11-30 Checking the oil level ....................................... 11-30
Recommended grade and viscosity ................ 11-31 Automatic transmission fluid ...................... 11-32
Checking the fluid level .................................... 11-32
Recommended fluid ......................................... 11-34
Front differential gear oil (AT vehicles) ...... 11-35 Checking the oil level ....................................... 11-35
Recommended grade and viscosity ............... 11-35
Rear differential gear oil ............................... 11-36 Checking the gear oil level .............................. 11-36
Recommended grade and viscosity ............... 11-37
Power steering fluid ...................................... 11-38 Checking the fluid level .................................... 11-38
Recommended fluid ......................................... 11-39
Brake fluid ..................................................... 11-40 Checking the fluid level .................................... 11-40
Recommended brake fluid ............................... 11-40
Clutch fluid (MT vehicles) ............................ 11-41 Checking the fluid level .................................... 11-41
Recommended clutch fluid .............................. 11-42
Brake booster ................................................ 11-42
Brake pedal .................................................... 11-43 Checking the brake pedal free play ................ 11-43
Checking the brake pedal reserve distance ... 11-43
Clutch pedal (MT vehicles) ........................... 11-44 Checking the clutch function .......................... 11-44
Checking the clutch pedal free play ............... 11-44
Replacement of brake pad and lining ......... 11-45 Breaking-in of new brake pads and linings .... 11-45
Parking brake stroke .................................... 11-46
Tires and wheels ........................................... 11-47

11 -3 5
Maintenance and service
– CONTINUED –
Front differential gear oil (AT vehi-
cles) „Checking the oil level
1) Yellow handle
1. Park the vehicle on a level surface and stop the en-
gine.
2. Pull out the dipstick, wipe it clean, and insert it
again. 1) Upper level
2) Lower level
3. Pull out the dipstick again and check the oil level on
it. If it is below the lower level, add oil to bring the level
up to the upper level. „ Recommended grade and viscosity
Each oil manufacturer has its own base oils and addi-
tives. Never use different brands together.
Oil grade:
API classification GL-5
1
UGB134EB
L F
1 2
HSB040BB

11 - 3 6
Maintenance and service
SAE viscosity No. and applicable temperature
Rear differential gear oil „
Checking the gear oil level
Your vehicle may be equipped with a rear differential
protector. The differential protector provides protec-
tion to the rear differential assembly during off-road
use. Removal of the rear differential protector is not re-
quired when checking the oil level.
1) Filler plug
2) Drain plug-30 -20 -10 0 10 20 30 40-20 0 60 20
80W
75W/90 80 100
40
85W 90
HSB036BA
2 1HSB042BB