2005 SUBARU IMPREZA engine

7-22
Starting and operating
Automatic transmission
The automatic transmission is electronically controlled
with 4-forward speeds and 1-reverse speed.
NOTE
Immediately after a disconnected battery is recon-
nected (Turbo model only) or ATF (automatic
transmission fluid) is replaced, you may feel that
the automatic transmission operation is some-
what unusual.
This results from erasure or invalidation of data
the on-board computer has collected and stored in memory to allow the transmission to shift at the
most appropriate times for the current condition
of your vehicle. Optimized shifting will be restored
as the vehicle continues to be driven for a while.
Do not shift from the “P” or “N” position into
the “D”, “3”, “2”, “1” or “R” position while de-
pressing the accelerator pedal. This may cause
the vehicle to jump forward or backward.
y
Shift into the “P” or “R” position only after
the vehicle is completely stopped. Shifting
while the vehicle is moving may cause damage
to the transmission.y Do not race the engine for more than five sec-
onds in any position except the “N” or “P” po-
sition when the brake is set or the tires are on
blocks. This may cause the automatic transmis-
sion fluid to overheat. y Avoid shifting from one of the forward driving
positions into the “R” position or vice versa un-
til the vehicle has completely stopped. Such
shifting may cause damage to the transmis-
sion.

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Starting and operating
– CONTINUED –
„Selector lever for automatic transmis- sion
: With the brake pedal depressed, move the lever along the gate.
: Move the lever along the gate.
The selector lever has seven positions. T P (Park)
This position is for parking the vehicle and starting the
engine.
In this position, the transmission is mechanically
locked to prevent the vehicle from rolling freely.
When you park the vehicle, first set the parking brake
fully, then shift into the “P” position. Do not hold the ve-
hicle with only the transmission.
P
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HS7009AA
HS7010BA

7-24
Starting and operating
A shift interlock function is employed in the automatic
transmission system to ensure safe starting of the ve-
hicle.
To shift the selector lever from the “P” to the any other
position, you have to depress the brake pedal fully
when the ignition switch is in the “ON” position. This
prevents the vehicle from lurching when it is started.
If the shift lever does not move from the “P” position
with the brake pedal depressed, refer to the “Shift lock
release” section in this chapter. T
R (Reverse)
This position is for backing the vehicle.
To shift from the “N” to “R” position, first stop the vehi-
cle completely then move the lever to the “R” position. T N (Neutral)
This position is for restarting a stalled engine.
In this position the wheels and transmission are not
locked. In this position, the transmission is neutral; the
vehicle will roll freely, even on the slightest incline un-
less the parking brake or foot brake is on.
NOTE (Except Turbo models)
If you stop the engine with the selector lever in the
“N” position, move the selector lever to the “P”
position immediately. Otherwise, you may find that the selector lever soon cannot be moved to
the “P” position. If you find that the selector lever
cannot be moved from the “N” position to the “P”
position, turn the ignition switch to the “ON” posi-
tion and try again.
Do not drive the vehicle with the selector lever
in the “N” (neutral) position. Engine braking
has no effect in this condition and the risk of an
accident is consequently increased.
T D (Drive)
This position is for normal driving.
The transmission automatically shifts into a suitable
gear from 1st to 4th according to the vehicle speed
and the acceleration you require.
When more acceleration is required in this position,
press the accelerator pedal fully to the floor and hold
that position. The transmission will automatically
downshift to 3rd, 2nd or 1st gear. When you release
the pedal, the transmission will return to the original
gear position.

7-25
Starting and operating
– CONTINUED –
VWhile climbing a grade
When driving up hill, undesired upshift to 4th gear is
prevented from taking place when the accelerator
pedal is released. This minimizes the chances of sub-
sequent downshifting to a lower gear when accelerat-
ing again. This prevents repeated upshifting and
downshifting resulting in a smoother operation of the vehicle.
NOTE
The transmission may downshift to 2nd or 1st
gear, depending on the way the accelerator pedal
is pressed to accelerate the vehicle again. V While going down a hill
When descending a steep hill, depressing the brake
pedal will cause the transmission to downshift to 3rd
gear, thus applying engine braking. Reacceleration for
a short time will cause the transmission to upshift nor-
mally.
NOTE
In some cases, depressing the brake pedal on a
downhill grade does not result in an automatic
downshift to 3rd gear. This can happen when the
automatic transmission fluid temperature is very
low, for example, during driving shortly after the
vehicle has been parked for an extended period of time. When the ATF temperature has risen to a cer-tain level, automatic downshift normally takes
place. In the meantime, downshift manually for en-
gine braking as required.
Also, downshifting when braking downhill will not
occur at speeds above approximately 48 mph (78 km/h). T
3 (Third)
This position is for using engine braking when going
down a hill or for climbing a grade.
The transmission automatically shifts into a suitable
gear from 1st to 3rd according to the vehicle speed
and the acceleration you require.
When more acceleration is required in this position,
press the accelerator pedal fully to the floor and hold
that position. The transmission will automatically
downshift to 2nd or 1st gear. When you release the
pedal, the transmission will return to the original gear
position. T 2 (Second)
This position is for using engine braking when going
down a hill or for climbing a steep grade.
In this position, the transmission holds in the 2nd gear.
Use this position when starting off from a standstill on
slippery road surfaces such as mud or snow. It will en-

7-26
Starting and operating
sure greater traction. T
1 (First)
This position is for driving up or down very steep
grades, or driving through mud or sand, or on slippery
surfaces. In this position, the transmission holds in the
1st gear. T Maximum speeds
The following tables show the maximum speeds that
are possible with each different gear.
When shifting down a gear, it is important to confirm
that the current vehicle speed is not in excess of the
Maximum Allowable Speed of the gear which is about
to be selected. mph (km/h)
NOTE
In order to prevent over-revving during decelera-
tion of the vehicle, the transmission will remain in
the current gear if the speed of the vehicle is in ex-
cess of the Maximum Allowable Speed for the gear
to which the selector lever has been moved.
When shifting down a gear, ensure that the ve-
hicle is not travelling at a speed exceeding the
Maximum Allowable Speed for the gear which
is about to be selected. Failure to observe this
precaution can lead to engine over-revving and
this in turn can result in engine damage.
In addition, sudden application of engine
brakes when the vehicle is travelling on a slip-
pery surface can lead to wheel locking; as a2.5-liter non-turbo
models 2.0-liter turbo models
1 28 (45) 28 (45)
2 62 (99) 58 (93)
3 95 (153) 99 (158)

7-27
Starting and operating
– CONTINUED –
consequence, control of the vehicle may be lost
and the risk of an accident increased.
T Driving tips
y Always apply the foot or parking brake when the ve-
hicle is stopped in the “D”, “3”, “2”, “1” or “R” position. y Always set the parking brake when parking your ve-
hicle. Do not hold the vehicle with only the transmis-
sion.y Do not keep the vehicle in a stationary position on
an uphill grade by using the “D”, “3”, “2”, or “1” position.
Use the brake instead.
The engine may, on rare occasions, knock when the
vehicle rapidly accelerates or rapidly pulls away from
a standstill. This phenomenon is not an indication of a
problem in your vehicle. „ Shift lock release
If the selector lever does not move from the “P” posi-
tion with the brake pedal depressed and the ignition
switch in the “ON” position, perform the following
steps:
To override the shift lock:
1. Set the parking brake and stop the engine.
2. Take out the screwdriver from the tool bag. 3. Remove the cover by prying on the edge with the
screwdriver.
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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

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Starting and operating
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es 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 adjacent to the power steering pump
which is located at the right-front area of the en-
gine compartment. This noise is normal. It does
not indicate power steering system trouble.
Do not hold the steering wheel at the fully
locked position left or right for more than five
seconds. This may damage the power steering
pump.