Subaru Impreza 2003, Service Manual

Page: 1566 / 3610

4AT-34
AUTOMATIC TRANSMISSION
STALL TEST
5. Stall Test
A: INSPECTION
NOTE:
The stall test is of extreme importance in diagnos-
ing the condition of the automatic transmission and
the engine. It should be conducted to measure the
engine stall speeds in “R” and “2” ranges.
Purposes of the stall test:
• To check the operation of the automatic trans-
mission clutch.
• To check the operation of the torque converter
clutch.
• To check engine performance.
1) Check that throttle valve opens fully.
2) Check that engine oil level is correct.
3) Check that coolant level is correct.
4) Check that ATF level is correct.
5) Check that differential gear oil level is correct.
6) Increase ATF temperature to 70 to 80
°
C (158 to
176
°
F) by idling the engine for approx. 30 minutes
(with select lever set to “N” or “P”).
7) Place the 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, and shift the select lever to the “2” range.
Turn hold switch ON.
9) While forcibly depressing the foot brake pedal,
gradually depress the accelerator pedal until the
engine operates at full throttle.
10) When the engine speed is stabilized, record
that speed quickly and release the accelerator ped-
al.
11) Shift the select lever to “N” range, and cool
down the engine by idling it for more than one
minute.
12) If the stall speed in “2” range is higher than
specifications, low clutch slipping and 2-4 brake
slipping may occur. To identify it, conduct the same
test as above in “R” range.
13) Perform the stall tests with the select lever in
“D” range. Turn hold switch OFF.
NOTE:
• Do not continue the stall test for MORE THAN 5
SECONDS at a time (from closed throttle, fully
open throttle to stall speed reading). Failure to fol-
low this instruction causes the engine oil and ATF
to deteriorate and the clutch and brake to be ad-
versely affected.
• Be sure to cool down the engine for at least 1
minute after each stall test with the select lever set
in the “P” or “N” range and with the idle speed lower
than 1,200 rpm.
• 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):
1.6 L model: 2,400 — 3,000 rpm
2.0 L Non-turbo model: 2,200 — 2,700 rpm
2.0 L Turbo model: 2,900 — 3,500 rpm
2.5 L model: 2,100 — 2,600 rpm
(A) Brake pedal
(B) Accelerator pedal
(A) (B)
P
R
N
D
3
2
1
AT-00449