7A–11 AUTOMATIC TRANSMISSION (4L30–E)
Fluid Condition
FLUID CONDITION
NORMAL*CONTAMINATED
COLORRED OR LIGHT
BROWNBROWNNON–TRANSPARENT
/ PINKBROWN
DRAIN
REQUIRED?NOYESYESYES
CONTAMINA–
TIONNONEVery small amount of
foreign material in
bottom of panContamination by
coolant or other sourceLarge pieces of metal
or other foreign
material in bottom of
pan
CORRECT
LEVEL AND
CONDITION
1. LOW LEVEL:
A. Add fluid to
obtain proper
level & check for
external leaks.
B. Correct cause of
leak.
2. HIGH LEVEL:
– Remove excess
fluid– Remove both pans
– Change filter
– Flush cooler
– Add new fluid
– Check level– Repair/replace
radiator cooler
–Transmission
overhaul required
– Check for:
Damaged plates
and seals
Contaminated
solenoids
– Flush cooler
– Add new fluid
– Check level
–Transmission
overhaul required
– Flush cooler and
cooler lines
– Add new fluid
– Check level
*Fluid should be changed according to maintenance
schedule.
Te s t D r i v i n g
Some 4L30–E automatic transmission complaints will
require a test drive as a part of the diagnostic procedure.
Some codes will not set unless the vehicle is moving. The
purpose of the test drive is to duplicate the customer’s
complaint condition and set a current Powertrain Control
Module (PCM) trouble code. Perform this procedure
before each 4L30–E automatic transmission repair, and
again after repairs are made.
IMPORTANT:
Duplicate the condition under which the customer’s
complaint was observed.
Depending on the complaint, the line pressure gauge
and the scan tool may be required during the test
drive.
During the test drive, it is important to record all
necessary data from the areas being monitored, for
use in diagnosis. Also listen for and note any unusual
noises.
The following procedure should be used to test drive
4L30–E automatic transmission complaint vehicles:
1. Turn the ignition ON without starting the engine.
Check that the “CHECK TRANS” lamp comes on for
approximately 2 seconds and then goes out and
remains out.
If the lamp is flashing, GOTO Check Trans Indicator
in Transmission Control System (4L30–E) section.
If no serial data is present, GOTO OBD System
Check. Refer to Driveability and Emissions in
Engine section.
If the lamp stays ON or stays OFF, GOTO “Check
Trans” Check in Transmission Control System
(4L30–E) section.
2. Drive the vehicle. During the test drive, be sure that
the transmission achieves normal operating
temperature (approx. 20 minutes).
Allow the transmission to go through all of its gear
ranges, checking shift timing and firmness. Duplicate
the owner’s complaint condition as closely as
possible during the test drive.
3. If, during the test drive, the “CHECK TRANS” lamp
comes on, use the scan tool to check for trouble
codes.
4. If, during the test drive, a problem is felt, but the
“CHECK TRANS” lamp does not come on and no
trouble codes are present, drive the vehicle with the
PCM disconnected (manually shifting the vehicle).
In Manual L, the vehicle operates in first gear.
In Manual 2, the vehicle operates in third gear.
In Manual 3 or “D”, the vehicle operates in fourth
gear.
If the problem still exists with the PCM disconnected,
refer to Mechanical/Hydraulic Diagnosis in this
section.
5. If no problem has been found at this point, check all
underhood connections that supply power to the PCM
and ignition fuses. Physically and visually inspect all
the PCM harness connectors for loose or corroded
terminals. Inspect the PCM ground points.
7A–18
AUTOMATIC TRANSMISSION (4L30–E)
Chart 9c: Coastdown Harsh Shift Or Clunk At 3–2 Downshift
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15b:
Possible Causes
of High Line
Pressure in this
section
2Does DTC P1850 set?
Diagnose P1850
first
Replace band
apply solenoid
(PWM) (323)
Chart 10: Intermittent 4TH TO 2ND Gear Downshift At Steady Speed
StepActionYe sNo
1Check for consistent speed sensor reading with scan tool.
Was the reading correct?Replace mode
switch for
intermittent
contact.
Go to Step 2
21. Check for wiring harness damage or short to ground. If OK, go
to (2).
2. Check transmission speed sensor connections. If OK, go to
(3).
3. Replace transmission speed sensor.
Was the replacement complete?
—
Replace speed
sensor.
Chart 11: Engine Flare At Shifting During Turning Only (Usually With Warm Engine)
StepActionYe sNo
1Check for oil leaks at transmission.
Was the problem found?Replace
transmission oil
filter and gasket
—
Chart 12: Engine Flare During 1–2 Or 2–3 Shift
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15a:
Possible Causes
of Low Line
Pressure in this
section
21. Check for a stuck 1–2 accumulator valve (320).
2. Check for servo piston (106) leaks.
3. Check for a stuck band apply solenoid (323).
Was line pressure normal?
Repair or replace—
7A–19 AUTOMATIC TRANSMISSION (4L30–E)
Chart 13: Shudder Only During Torque Converter Clutch (TCC) Applying
StepActionYe sNo
11. 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.
2. 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:
3. From coast condition at 50 mph in “D” range (Normal mode),
depress the throttle to 1/4-1/3 throttle. If present, shudder will
occur within 5 seconds together with TCC application.(The
scan tool may be used to determine the exact time of TCC
applying)
Was the problem found?
Replace
transmission fluid
and filter (remove
both pans) and
flush cooler lines.
Replace
converter
assembly and
O-ring on turbine
shaft
Perform
mechanical
inspection of
other drivetrain
components.
Chart 14: Possible Causes Of Transmission Noise
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.
Condition
Possible causeCorrection
Whine or BuzzOil level lowFill with ATF, check for external
leaks.
Plugged or restricted oil filterInspect oil filter.
Replace oil filter or ATF as necessary.
Damaged oil filter gasketReplace oil filter gasket.
Knocking noise from front of
transmission
Loose bolts (Converter to flex plate)Tighten to specifications.
transmission.Cracked or broken flex plateReplace flex plate.
Converter damagedReplace converter.
Knocking noise while driving, mostly
on acceleration.Transmission mount loose or brokenTighten mount bolts or replace
transmission mount.
Cooler line mounts loose or brokenTighten or replace cooler line
mounts.
Cooler lines touching body or frameRepair or replace as necessary.
Knocking noise when vehicle is
stationary
Loose flex plate mounting boltsTighten to specifications.
stationary.Cracked or broken flex plateReplace flex plate.
Damaged converterReplace converter.
