Subaru IMPREZA GD 2007 Series Manual page 2539

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AUTOMATIC TRANSMISSION
5. Stall Test
A: INSPECTION
NOTE:
The stall test is extremely important in diagnosing
the condition of an automatic transmission and en-
gine. It is necessary to perform this test to measure
the engine stall speeds in the "R" and "2" ranges.
Purposes of the stall test:
• Operational check of the automatic transmission
clutch
• Operational check of the torque converter clutch
• Engine performance check
1) Check that the throttle valve fully opens.
2) Check that the engine oil level is correct.
3) Check that the engine coolant level is correct.
4) Check that the ATF level is correct.
5) Check that the differential gear oil level is cor-
rect.
6) Increase the ATF temperature to 70 to 80°C
(158 to 176°F) by idling the engine for approximate-
ly 30 minutes (with select lever set to "N" or "P").
7) Place wheel chocks at the front and rear of all
wheels and engage the parking brake.
8) Move the manual linkage to ensure it operates
properly. Shift the select lever to the "2" range.
9) While pressing hard on the foot brake pedal,
slowly depress the accelerator pedal to full throttle.
P
R
N
D
3
2
1
(A) Brake pedal
(B) Accelerator pedal
Stall speed (at sea level)
Specified value or below
Over specified value
Stall Test
(A) (B)
AT-00449
Range
• Throttle valve is not fully open
2, R • Engine malfunction
• One-way clutch of the torque converter is slipping
• Line pressure too low
D • Low clutch slipping
• One-way clutch malfunctioning
• Line pressure too low
R • Reverse clutch slipping
• Low & reverse brake slipping
• Line pressure too low
2 • Low clutch slipping
• 2-4 brake slipping
4AT-32
10) When the engine speed is stabilized, quickly
record the engine speed and release accelerator
pedal.
11) Shift the select lever to "N" range, and cool
down the engine by idling it for one minute or more.
12) If the stall speed in the "2" range is higher than
specifications, low clutch and 2-4 brake may slip.
To identify this, conduct the same test as above in
"R" range.
13) Perform the stall tests with the select lever in
"D" range.
NOTE:
• Do not continue the stall test for more than 5 sec-
onds at a time. (From closed throttle / full open
throttle to reading stall speed) If this instruction is
ignored, the engine oil and ATF oil may deteriorate,
and it may be detrimental to the clutch and brake.
• Be sure to cool down the engine for at least one
minute after each stall test with the select lever set
in the "P" or "N" range and with the idle speed of
1,200 rpm or less.
• If the stall speed is higher than the specified
range, attempt to finish the stall test in as short a
time as possible, in order to prevent the automatic
transmission from sustaining damage.
Stall speed (at sea level):
Non-turbo model:
2,200 — 2,700 rpm
Turbo model:
2,600 — 3,100 rpm
Cause