1995 ISUZU TROOPER Workshop Manual

AUTOMATIC TRANSMISSION (4L30·E) 7 A-33
CHART 10: INTERMITTENT 4TH TO 2ND GEAR DOWNSHIFT AT. STEADY SPEED
PERFORM PRELIMINARY INSPECTION FIRST!
Check for consistent speed
sensor reading
with TECH1
Replace mode switch for intermittent
contact
1-------1 Check for wiring harness damage L...------1 or short to ground
OK
Check transmission speed sensor
connections
OK
Replace transmission speed
sensor

7 A-34 AUTOMATIC TRANSMISSION (4L30-E)
CHART 11: ENGINE FLARE AT SHIFTING DURING TURNING ONLY
(USUALLY WITH
WARM ENGINE)
PERFORM PRELIMINARY INSPECTION FIRST!
Leak at transmission oil filter, gasket, or wrong filter type
Replace transmission oil filter and
gasket
CHART 12: ENGINE FLARE DURING 1-2 OR 2-3 SHIFT
PERFORM PRELIMINARY INSPECTION FIRST!
Normal line pressure
Check for 1-2 accumulator valve (320) stuck
Check for servo piston (106) leaks
Check
for band apply solenoid (323) stuck
( ) Refer
to Parts List at the end of this Section.
Check
line pressure (
Refer
to Line
Pressure chart) t~n.
Low line pressure
Use CHART 15a:
POSSIBLE CAUSES OF
LOW LINE PRESSURE ~fM!~e 71/1t 37
..

AUTOMATIC TRANSMISSION (4L30-E) 7 A-35
CHART 13: SHUDDER ONLY DURING TORQUE CONVERTER CLUTCH (TCC) APPLYING
PERFORM PRELIMINARY INSPECTION FIRST!
TCC shudder is one of the most commonly misdiagnosed conditions in
an automatic transmission. The key to diagnosing TCC shudder is to note when it happens and under what conditions. Once the TCC has
been fully applied, it is nearly impossible to make it shudder. TCC shudder {short burst of noise normally less than 1 second) will only
occur during clutch applying. It is not a steady state condition.
Drive
until whole drivetrain is at normal operating temperature.
-On 4WD vehicles, the test must be performed with transfer case selector lever in "2H" position.
- Shudder is a SHORT BURST OF NOISE NORMALLY LESS THAN 1
SECOND IN DURATION, and can be induced by the following maneuver:
From coast condition at
50 mph in "D" range {Normal mode), depress
the throttle to 1/4-1/3 throttle. If present, shudder {short burst of noise normally less than 1 sec.) will occur within 5 seconds together with TCC applying. {TECH1 may be used to determine the exact time of TCC applying)
YES
Replace transmission fluid and filter {remove both pans) and flush
cooler lines.
Replace
converter assembly and 0-ring on turbine shaft.
,__ __ N_o ___ ---<1 Perform mechanical inspection of I j other drivetrain components.

7 A-36 AUTOMATIC TRANSMISSION (4L30-E)
CHART 14: POSSIBLE CAUSES OF TRANSMISSION NOISE
PERFORM PRELIMINARY INSPECTION FIRST!
'\f CAUTION:
Before checking transmission for what is believed to be transmission noise,
ensure presence and
positioning of insulating plugs, pads etc. Also make
sure
that noise does not come from other drivetrain components.
1. WHINE OR BUZZ:
-
Oil level low
-Plugged or restricted oil filter
- Damaged oil filter gasket
2. KNOCKING NOISE FROM FRONT OF TRANSMISSION:
-Loose bolts (Converter to flex plate)
- Cracked or broken flex plate
-Converterdamaged
3. KNOCKING NOISE WHILE DRIVING- MOSTLY ON ACCELERATION:
-Transmission mount loose or broken
-
Cooler line mounts loose or broken
-
Cooler lines touching body or frame
4. KNOCKING NOISE WHEN VEHICLE IS STATIONARY:
-Loose flex plate mounting bolts
-Cracked or broken flex plate
-Damaged converter
II

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AUTOMATIC TRANSMISSION (4L30..E) 7 A-37
CHART 15a: POSSIBLE CAUSES OF LOW LINE PRESSURE
Small
valve
body
Oil pump
{
Check oil level I
OK
Check for defective throttle position sensor I
OK
Check for plugged, loose, or damaged oil filter (79) I
OK
Check for force motor plunger (404) stuck. (Remove force motor. Shake and listen for rattle.) I
OK
Check for feed limit valve (412) stuck I
OK
------------------------------------------------------------------------
Check for loose bolts (4 & 5) I
OK
Check for pressure regulator valve (208) stuck I
OK
Check for boost valve (205) stuck I
OK
Check for intermediate oil passages to pressure regulator valve blocked I
OK
Check for defective oil pump (9, 201, 202 & 209) I
OK
Check for internal leaks -Check balls missing or out of location in valve bodies -Seals cut or damaged
-Gaskets defective, etc.
( ) Refer to Parts List at the end
of this Section.

7 A-38 AUTOMATIC TRANSMISSION (4L30-E)
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Q w > 0 ::E w a:
2 0 CiS (I)
i (I) 2
~ .....
CHART 15b: POSSIBLE CAUSES OF HIGH LINE PRESSURE
PERFORM PRELIMINARY INSPECTION FIRST! I
Small
valve
body
Oil
pump
NOTE: If transmission is operating in back-up mode, high line pressure will be
present.
Also, when TECH1 is connected, line pressure will be at maximum
during shifts.
Check for defective throttle position sensor I
OK
Check for force motor plunger (404) stuck.
(Remove force motor. Shake and listen for rattle.) (Open circuit/Intermittent)
OK
Check for feed limit valve (412) stuck I
OK
--------------------------------------------
Check for loose bolts (4 & 5) I
OK
Check for pressure regulator valve (208) stuck I
OK
Check for boost valve (205) stuck I
OK
Check for internal leaks
-Check balls missing or out of location in valve bodies -Seals cut or missing
-Gaskets defective, etc.
( ) Refer to Parts List at the end
of this Section.

AUTOMATIC TRANSMISSION (4L30-E) 7 A-39
CHART 16: POSSIBLE CAUSES OF TRANSMISSION FLUID LEAKS
Before attempting to correct an oil leak, the actual source of the leak must be determined. In many cases,
the source
of the leak may be difficult to determine due to "wind flow" around the engine and
transmission.
The suspected area
should be wiped clean of all oil before inspecting for the source of the leak.
Oil leaks
around the engine and transmission are generally carried toward the rear of the car by the air
stream. For example, a transmission "OIL FILLER TUBE TO CASE" leak will sometimes appear as a leak at
the rear
of the transmission. In determining the source of an leak, the following two checks should be
made:
1. With the engine running, check for external line pressure leaks.
2. With the engine off, check for oil leaks due to the raised oil level caused by drainback of converter oil
into the transmission.
Overfill condition
Two possible causes of fluid
leaks
Sealing
malfunction
Check at POSSIBLE CAUSES OF FLUID LEAKS DUE TO SEALING
MALFUNCTION (See nex~

7 A-40 AUTOMATIC TRANSMISSION (4L30-E)
POSSIBLE CAUSES OF FLUID LEAKS
DUE
TO SEALING MALFUNCTION
A) Transmission vent (Breather)
B) Electrical connector (Main case) seal
C) Electrical connector (Adapter case) seal
D) Oil filler tube seal/ Tube "LOADING" one side
of seal/seal 0-ring at tubes junction
E) Line pressure tap plug
F) Converter housing lip seal
G) Converter housing attaching bolts not correctly
torqued
H) Oil pan gasket (Adapter case)
J) Selector shaft seal
Kl
Oil pan gasket (Main case)
L) Oil drain plug gasket
M) Extension (Adapter)
to main case gasket
Nl Extension (Adapter) lip seal
P) Speed sensor 0-ring
R) Oil cooler connectors (2)
S) Adapter case seal rings (2)
~·
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..