1996 SUBARU LEGACY check engine

3. Performance Test
A: STALL TEST
1. GENERAL
The stall test is of extreme importance in diagnosing the
condition of the automatic transmission and the engine. It
should be conducted to measure the engine stall speeds in
all shift ranges except the P and N ranges.
Purposes of the stall test:
1) To check the operation of the automatic transmission
clutch.
2) To check the operation of the torque converter clutch.
3) To check engine performance.
2. TEST METHODS
Preparations before test:


1Check that throttle valve opens fully.


2Check that engine oil level is correct.


3Check that coolant level is correct.


4Check that ATF level is correct.


5Check that differential gear oil level is correct.


6Increase ATF temperature to 50 to 80°C (122 to 176°F)
by idling the engine for approximately 30 minutes (with
select lever set to“N”or“P”).
1) Install an engine tachometer at a location visible from
the driver’s compartment and mark the stall speed range
on the tachometer scale.
2) Place the wheel chocks at the front and rear of all
wheels and engage the parking brake.
3) Move the manual linkage to ensure it operates properly,
and shift the select lever to the 2 range.
B3M0286B
4) While forcibly depressing the foot brake pedal, gradu-
ally depress the accelerator pedal until the engine operates
at full throttle.
5) When the engine speed is stabilized, read that speed
quickly and release the accelerator pedal.
6) Shift the select lever to Neutral, and cool down the
engine by idling it for more than one minute.
7) Record the stall speed.
8) If stall speed in 2 range is higher than specifications,
forward clutch slipping on brake band slipping may occur.
To identify it, conduct the same test as above in D range.
9) Perform the stall tests with the select lever in the R
range.
CAUTION:
Do not continue the stall test for MORE THAN FIVE
SECONDS at a time (from closed throttle, fully open
throttle to stall speed reading). Failure to follow this
instruction causes the engine oil and ATF to deterio-
rate and the clutch and brake band to be adversely
affected.
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3-2SERVICE PROCEDURE
3. Performance Test

B: TIME LAG TEST
1. GENERAL
If the shift lever is shifted while the engine is idling, there
will be a certain time elapse or lag before the shock can be
felt. This is used for checking the condition of the forward
clutch, reverse clutch, low & reverse brake, forward one-
way clutch and low one-way clutch.
CAUTION:
Perform the test at normal operation fluid tempera-
ture 60 to 80°C (140 to 176°F).
Be sure to allow a one minute interval between tests.
Make three measurements and take the average
value.
2. TEST METHODS
1) Fully apply the parking brake.
2) Start the engine.
Check idling speed (A/C OFF).
“N”range: 800±100 rpm
3) Shift the shift lever from“N”to“D”range.
Using a stop watch, measure the time it takes from shift-
ing the lever until the shock is felt.
Time lag: Less than 1.2 seconds
4) In same manner, measure the time lag for“N”,“R”.
Time lag: Less than 1.5 seconds
3. EVALUATION
1) If“N”,“D”time lag is longer than specified:
Line pressure too low
Forward clutch worn
Low one-way clutch not operating properly
2) If“N”,“R”time lag is longer than specified:
Line pressure too low
Reverse clutch worn
Low & reverse brake worn
Forward one-way clutch not operating properly
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3-2SERVICE PROCEDURE
3. Performance Test

C: LINE PRESSURE TEST
1. GENERAL
If the clutch or the brake band shows a sign of slippage or
shifting sensation is not correct, the line pressure should be
checked.
Excessive shocks during upshifting or shifting takes
place at a higher point than under normal circumstances,
may be due to the line pressure being too high.
Slippage or inability to operate the vehicle may, in most
cases, be due to loss of oil pressure for the operation of
the clutch, brake band or control valve.
G3M0869
1) Line pressure measurement (under no load)
CAUTION:
Before measuring line pressure, jack-up front
wheels (front-wheel-drive model) or all wheels (4-wheel
drive model).
Maintain temperature of ATF at approximately 50°C
(122°F) during measurement.
(ATF will reach the above temperature after idling the
engine for approximately 30 minutes with select lever
in“N”or“P”.)
G3M0869
2) Line pressure measurement (under heavy load)
CAUTION:
Before measuring line pressure, apply both foot and
parking brakes with all wheels chocked (Same as for
“stall”test conditions).
Measure line pressure when select lever is in“R”,
“2”with engine under stall conditions.
Measure line pressure within 5 seconds after shift-
ing the select lever to each position. (If line pressure
needs to be measured again, allow the engine to idle
and then stop. Wait for at least one minute before mea-
surement.)
Maintain the temperature of ATF at approximately
50°C (122°F) during measurement. (ATF will reach the
above temperature after idling the engine for approxi-
mately 30 minutes with the select lever in“N”or“P”.)
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3-2SERVICE PROCEDURE
3. Performance Test

G3M0317
2. TEST METHODS
1) Temporarily attach the ST to a suitable place in the
driver’s compartment, remove the blind plug located in
front of the toe board and pass the hose of the ST to the
engine compartment.
ST 498575400 OIL PRESSURE GAUGE ASSY


1Pressure gauge hose


2Hole in toe board (blank cap hole)


3Brake pedal
G3M0869
2) Remove the test plug and install ST1 instead.
3) Connect ST1 with ST2.
ST1 498897200 OIL PRESSURE GAUGE ADAPTER
ST2 498575400 OIL PRESSURE GAUGE ASSY
4) Check for duty ratio changes by opening and closing
throttle valve using select monitor.
5) Check line pressure in accordance with the following
chart.
3. EVALUATION
NOTE:
Under no load:“D”
Under full load:“R”,“2”
(With engine running at stall speed)

Unit: kPa (kg/cm2, psi)
Line pressure
Duty ratio (%)“2”range“R”range“D”range
2200 cc 2500 cc
51,147—1,344
(11.7—13.1, 166—195)1,275—1,569
(13.0—16.0, 185—228)—
22——765—902
(7.8—9.2, 111—131)
100——235—481
(2.4—4.9, 34—70)392—490
(4.0—5.0, 57—71)
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3-2SERVICE PROCEDURE
3. Performance Test

G3M0870
D: TRANSFER CLUTCH PRESSURE TEST
Check transfer clutch pressure in accordance with the fol-
lowing chart in the same manner as with line pressure.
ST 499897700 OIL PRESSURE ADAPTER SET
ST 498575400 OIL PRESSURE GAUGE ASSY
AWD mode:“D”range
FWD mode:“P”range, engine speed 2000 rpm
CAUTION:
Before setting in FWD mode, install spare fuse on FWD
mode switch.
Unit: kPa (kg/cm2, psi)
Duty ratio
(%)AWD mode FWD mode
5667—804
(6.8—8.2, 97—117)667—804
(6.8—8.2, 97—117)
40137—226
(1.4—2.3, 20—33)—
950
(0, 0)—
If oil pressure is not produced or if it does not change in the
AWD mode, the duty solenoid C or transfer valve assem-
bly may be malfunctioning. If oil pressure is produced in the
FWD mode, the problem is similar to that in the AWD
mode.
E: ROAD TEST
1. GENERAL
Road tests should be conducted to properly diagnose the
condition of the automatic transmission.
CAUTION:
When performing test, do not exceed posted speed
limit.
2. CHECKING FOR SHIFT PATTERNS
Check“kick-down”.
D range: 1st
←
→2nd←
→3rd←
→4th
3 range: 1st←
→2nd←
→3rd←4th
2 range: 2nd←3rd←4th
1 range: 1st←2nd←3rd←4th
3. CHECK FOR ENGINE BRAKE OPERATION
Engine brake operation:
D range→4th gear
3 range→3rd gear
2 range→2nd gear
1 range→1st gear
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3-2SERVICE PROCEDURE
3. Performance Test

B3M0417A
8) Insert the thread portion of the other inner cable end
into the connector hole of the selector lever, and fix the
other outer cable end to the bracket.
9) Adjust the inner cable length.
(1) Put connector into contact with nut

2.
(2) Tighten nut

1.
Tightening torque:
7.4±2.0 N⋅m (0.75±0.2 kg-m, 5.4±1.4 ft-lb)
10) After completion of fitting, make sure that the selector
lever operates smoothly all across the operating range.
11) Connect the harnesses and check the following items.
(1) The engine starts operating when selector lever is
in position“P”, but not in other positions.
(2) The back-up light is lit when the selector lever is in
position“R”, but not in other positions.
B3M0348A
12) Check selector lever operation.
WARNING:
Stop the engine while checking operation of selector
lever.
(1) Check that selector lever does not move from“N”
to“R”without pushing the button.
(2) Check that selector lever does not move from“R”
to“P”without pushing the button.
(3) Check that selector lever does not move from“P”
to“R”without pushing the button and the brake pedal
depressed. [With ignition key set at“ON”.]
(4) Check that selector lever does not move from“3”to
“2”without pushing the button.
13) Check shift-lock system.
(1) Ensure ignition switch rotates from“ACC”to
“LOCK”when the selector lever is set at“P”. Also check
that ignition key can be removed from the“LOCK”posi-
tion only.
(2) Ensure selector lever moves from“P”to any other
position when the brake pedal is depressed with igni-
tion key set at“ON”or“START”.
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3-3SERVICE PROCEDURE
2. Automatic Transmission

Symptom and possible cause Remedy
5. Noises when cornering


1Damaged differential gear. Replace.


2Excessive wear or damage of thrust washer. Replace.


3Broken pinion mate shaft. Replace.


4Seized or damaged side bearing. Replace.
6. Gear noises
Since noises from engine, muffler, transmission, propeller shaft, wheel bearings, tires, and body are sometimes mistaken for noises
from differential assembly, be careful in checking them. Inspection methods to locate noises include coasting, accelerating, cruising,
and jacking-up all four wheels. Perform these inspections according to condition of trouble. When listening to noises, shift gears into
four wheel drive and fourth speed position, trying to pick up only differential noise.


1Improper tooth contact of hypoid gear. Readjust or replace hypoid gear set.


2Improper backlash for hypoid gear. Readjust.


3Scored or chipped teeth of hypoid gear. Replace hypoid gear set.


4Seized hypoid gear. Replace hypoid gear set.


5Improper preload for front or rear bearings. Readjust.


6Seized, scored, or chipped front or rear bearing. Replace.


7Seized, scored, or chipped side bearing. Replace.


8Vibrating differential carrier. Replace.
2. Propeller Shaft
Symptom and possible cause Remedy
1. Vibration of propeller shaft
Vibration is caused by propeller shaft during operation and is transferred to vehicle body. Generally vibration increase in proportion to
vehicle speed.


1Worn or damaged universal joint. Replace.


2Unbalanced propeller shaft due to bend or dent. Replace.


3Loose installation of propeller shaft. Retighten.


4Worn or damaged center bearing and damaged center mount-
ing rubber.Replace.
2. Tapping when starting and noise while cruising, caused by propeller shaft.


1Worn or damaged universal joint. Replace.


2Worn spline of sleeve yoke. Replace.


3Loose installation of propeller shaft. Retighten.


4Loose installation of joint. Replace.


5Worn or damaged center bearing and damaged center mount-
ing rubber.Replace.
NOTE:
Vibration while cruising may be caused by an unbalanced
tire, improper tire inflation pressure, improper wheel
alignment, etc.
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3-4DIAGNOSTICS
1. Rear Differential - 2. Propeller Shaft

Symptom and possible cause Remedy
5. Noises when cornering


1Damaged differential gear. Replace.


2Excessive wear or damage of thrust washer. Replace.


3Broken pinion mate shaft. Replace.


4Seized or damaged side bearing. Replace.
6. Gear noises
Since noises from engine, muffler, transmission, propeller shaft, wheel bearings, tires, and body are sometimes mistaken for noises
from differential assembly, be careful in checking them. Inspection methods to locate noises include coasting, accelerating, cruising,
and jacking-up all four wheels. Perform these inspections according to condition of trouble. When listening to noises, shift gears into
four wheel drive and fourth speed position, trying to pick up only differential noise.


1Improper tooth contact of hypoid gear. Readjust or replace hypoid gear set.


2Improper backlash for hypoid gear. Readjust.


3Scored or chipped teeth of hypoid gear. Replace hypoid gear set.


4Seized hypoid gear. Replace hypoid gear set.


5Improper preload for front or rear bearings. Readjust.


6Seized, scored, or chipped front or rear bearing. Replace.


7Seized, scored, or chipped side bearing. Replace.


8Vibrating differential carrier. Replace.
2. Propeller Shaft
Symptom and possible cause Remedy
1. Vibration of propeller shaft
Vibration is caused by propeller shaft during operation and is transferred to vehicle body. Generally vibration increase in proportion to
vehicle speed.


1Worn or damaged universal joint. Replace.


2Unbalanced propeller shaft due to bend or dent. Replace.


3Loose installation of propeller shaft. Retighten.


4Worn or damaged center bearing and damaged center mount-
ing rubber.Replace.
2. Tapping when starting and noise while cruising, caused by propeller shaft.


1Worn or damaged universal joint. Replace.


2Worn spline of sleeve yoke. Replace.


3Loose installation of propeller shaft. Retighten.


4Loose installation of joint. Replace.


5Worn or damaged center bearing and damaged center mount-
ing rubber.Replace.
NOTE:
Vibration while cruising may be caused by an unbalanced
tire, improper tire inflation pressure, improper wheel
alignment, etc.
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3-4DIAGNOSTICS
1. Rear Differential - 2. Propeller Shaft