
Ignition Coil —
Coil On Plug
The engine uses eight separate coil per plug units. Each coil per plug unit is controlled by the
powertrain control module (PCM).
Each coil per plug unit is mounted directly above each spark plug and activates its own spark plug in
the correct sequence as controlled by the PCM.
Refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual for additional information on the
ignition system.
Intake Air Temperature (IAT) Sensor
The intake air temperature (IAT) sensor provides the sequential fuel injection (SFI) system mixture
temperature information. The IAT sensor is used both as a density corrector for air flow calculation and
to proportion cold enrichment fuel flow. The IAT sensor is installed in the air cleaner inlet tube. The IAT
sensor is also used in determining EPC pressures.
Mass Air Flow (MAF) Sensor
The mass air flow (MAF) sensor measures the mass of air flowing into the engine. The MAF sensor
output signal is used by the powertrain control module to calculate injector pulse width. For
transmission strategies, the mass air flow sensor is used to regulate EPC, shift and torque converter
clutch scheduling.
Transmission Control Switch (TCS) and Transmission Control Indicator Lamp (TCIL)
The transmission control switch (TCS) is a momentary contact switch. When the switch is pressed, a
signal is sent to the PCM to allow automatic shifts from first through fourth gears or first through third
gears only. The PCM energizes the transmission control indicator lamp (TCIL) when the switch is off.
The TCIL indicates overdrive cancel mode activated (lamp on). When the TCIL is flashing, it indicates
electronic pressure control (EPC) circuit shorted or a monitored sensor failure.
Throttle Position (TP) Sensor
The throttle position (TP) sensor is a potentiometer mounted on the throttle body. The TP sensor
detects the position of the throttle plate and sends this information to the PCM. The TP sensor is used
for shift scheduling, electronic pressure control (EPC) and TCC control.
Digital Transmission Range (TR) Sensor
The digital transmission range (TR) sensor is located on the outside of the transmission at the manual
lever. The digital sensor completes the start circuit in PARK and NEUTRAL, and the back- up lamp
circuit in REVERSE. The digital sensor also opens/closes a set of four switches that are monitored by
the PCM to determine the position of the manual lever (P, R, N, D, 2, 1).
Output Shaft Speed (OSS) Sensor
The output shaft speed (OSS) sensor is a magnetic pickup, located at the output shaft ring gear, that
sends a signal to the powertrain control module (PCM) to indicate transmission output shaft speed.
The OSS sensor is used for torque converter clutch (TCC) control, shift scheduling and to determine
electronic pressure control (EPC).
Electronic Pressure Control (EPC) Solenoid
The EPC solenoid regulates transmission pressure. EPC valve pressure is used to control line
pressure.
Torque Converter Clutch (TCC) Solenoid Klj . 2 ba
42003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

CAUTION: The use of any other type of transmission fluid than specified could result in
transmission failure.
If fluid needs to be added, add fluid in 0.25L (1/2 pint) increments through the filler tube. Do not overfill
the fluid. For fluid type, refer to the specification chart.
Fluid Condition Check
1. Check the fluid level.
2. Observe the color and the odor. The color under normal circumstances should be dark reddish, not brown or black or have a burnt odor.
3. Hold the fluid level indicator over a white facial tissue and allow the fluid to drip onto the facial tissue and examine the stain.
4. If evidence of solid material is found, the transmission fluid pan should be removed for further inspection.
5. If the stain is a foamy pink color this may indicate coolant in the transmission. The engine cooling system should also be inspected at this time.
6. If fluid contamination or transmission failure is confirmed by the sediment in the bottom of the fluid pan, the transmission must be disassembled and completely cleaned. This includes the
torque converter and cooler tubes. The oil- to-air cooler will need to be installed.
7. Carry out diagnostic checks and adjustments. Refer to Diagnosis By Symptom in this section. Klj . 3 ba
32003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Leakage Inspection
CAUTION: Do not try to stop the fluid leak by increasing the torque beyond specifications.
This may cause damage to the case threads.
Check the fluid filler tube connection at the transmission case. If leakage is found here, install a new
grommet.
Check the VSS plug or VSS sensor O-ring (model dependent). If leakage is found install a new O- ring.
Check fluid lines and fittings between the transmission and the cooler in the radiator tank for
looseness, wear, or damage. If leakage cannot be stopped by tightening a fluid tube nut, install new
parts. When fluid is found leaking between the case and cooler line fitting, check for missing or
damaged O- ring, then tighten the fitting to maximum specification.
If the leak continues, install a new cooler line fitting and tighten to specification. The same procedure
should be followed for fluid leaks between the radiator cooler and the cooler line fittings in this section;
refer to Section 307 - 02 .
Check the engine coolant in the radiator. If transmission fluid is present in the coolant, the cooler in the
radiator is probably leaking.
The cooler can be further checked for leaks by disconnecting the lines for the cooler fittings and
applying no more than 345 kPa (50 psi) air pressure to the fittings. Remove the radiator cap to relieve
the pressure buildup at the exterior of the oil cooler tank. If the cooler is leaking and or will not hold
pressure, install a new cooler.
If leakage is found at the transmission range selector lever, install a new seal.
If leakage is found at the transmission internal harness connector, install a new O- ring. 4R70W External Sealing SECTION 307-
01: Automatic Transaxle/Transmission 2003 Mustang Workshop Manual Klj . 1 ba
52003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

Item Part Number Description
1 7902 Torque converter
2 7A248 Front pump seal
3 7A248 Front pump seal
4 N605789-S101 Bolt
5 7A106 Front pump body assembly
6 7A136 Pump gasket
7 390318-
S2 Pipe plug —
1/8 —27 Dryseal tapered 8 7005 Case
9 7034 Vent
10 N811757-S100 Speed sensor seal
11 7H103 Output shaft speed (OSS) sensor
12 7B498 Manual control lever seal assembly
13 7086 Extension housing gasket
14 7A039 Extension housing
15 N803737-S1101 Bolt —
M8-1.25 x 30 15 N606047-S101 Bolt —
M8-1.25 x 70 15 N803521-S1101 Bolt —
M8-1.25 x 1.25 x 0.54 15 N811524-S101 Bolt —
M8-1.25 x 42 16 7052 Oil seal
17 7Z276 Seal —
bulkhead assembly 18 7G276 Bulkhead assembly wiring connector
19 7G276 Molded lead frame
20 7A194 Transmission fluid pan
21 7A191 Gasket Klj . 2 ba
52003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

Fluid Leakage in Torque Converter Area
In diagnosing and correcting fluid leaks in the front pump support and gear and torque converter area,
use the following procedures to locate the exact cause of the leakage. Leakage at the front of
transmission, as evidenced by fluid around the torque converter housing, may have several sources.
By careful observation it is possible, in many instances, to pinpoint the source of leak before removing
the transmission from the vehicle. The paths which the fluid takes to reach the bottom of the torque
converter housing are shown in the illustration. The five steps following correspond with the numbers
in the illustration.
1. Fluid leaking by the front pump seal lip will tend to move along the impeller hub and onto the back of the impeller housing. Except in the case of a total seal failure, fluid leakage by the lip of
the seal will be deposited on the inside of the torque converter housing only, near the outside
diameter of the housing.
2. Fluid leakage by the outside diameter of the front pump seal and front pump body will follow the same path that leaks by the inside diameter of the front pump seal follow.
3. Fluid that leaks by a front pump to case bolt or pump gasket will be deposited on the inside of the torque converter housing only. Fluid will not be deposited on the back of the torque
converter.
4. Fluid leakage from the converter drain plug, (model dependent) converter seal weld or converter to flexplate stud weld will appear at the outside diameter of the torque converter on the back
face of the flexplate and in the converter housing only near the flexplate. Fluid leaks from the
torque converter will leave a ring of fluid around the inside of the torque converter housing.
5. NOTE: White facial tissue paper may aid in determining the color (red is transmission fluid) and
source of the leaking fluid.
Engine oil leaks are sometimes incorrectly diagnosed as transmission pump gasket leaks. The 22 7D273 Fluid tube connector
23 87650-S2 Converter drain plug Klj . 3 ba
52003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

following areas of possible leakage should also be checked to determine if engine oil leakage is
causing the concern.
a. Leakage at the engine valve cover gasket may allow oil to flow over the torque converter housing or seep down between the torque converter housing and cylinder block causing oil to
be present in or at the bottom of the torque converter housing.
b. Oil galley plug leaks will allow oil to flow down the rear face of the cylinder block to the bottom of the torque converter housing.
c. Leakage at the crankshaft rear oil seal will work back to the flexplate, and then into the torque converter housing.
d. Leakage at engine oil pressure sensor.
Leak Check Test 1. Remove the fluid level indicator and note the color of the fluid. Original factory fill fluid is dyed red to aid in determining if leakage is from the engine or transmission. Unless a considerable
amount of makeup fluid has been added or the fluid has been changed, the red color should
assist in pinpointing the leak.
2. Remove the torque converter housing cover. Clean off any fluid from the top and bottom of the torque converter housing, front of the case and rear face of the engine and oil pan. Clean the
torque converter area by washing with a suitable nonflammable solvent and blow dry with
compressed air.
3. Wash out the torque converter housing, the front of the flexplate and the converter drain plugs. The torque converter housing may be washed out using cleaning solvent and a squirt- type oil
can. Blow all washed areas dry with compressed air.
4. Start and run the engine until the transmission reaches its normal operating temperature. Observe the back of the cylinder block and top of the torque converter housing for evidence of
fluid leakage. Raise the vehicle on a hoist; refer to Section 100 - 02 and run the engine at fast
idle, then at engine idle, occasionally shifting to the Overdrive and Reverse ranges to increase
pressure within the transmission. Observe the front of the flexplate, back of the cylinder block
(in as far as possible), and inside the torque converter housing and front of the case. Run the
engine until fluid leakage is evident and the probable source of leakage can be determined.
Leak Check Test With Black Light Used With 12 Volt Master UV Diagnostic Inspection Kit
Oil soluble aniline or fluorescent dyes premixed at the rate of 2.5ml (1/2 teaspoon) of dye powder to
0.235L (1/2 pint) of transmission fluid have proved helpful in locating the source of fluid leakage. Such
dyes may be used to determine whether an engine oil or transmission fluid leak is present, or if the
fluid in the fluid cooler leaks into the engine cooling system. A black light must be used with the
fluorescent dye solution. Klj . 4 ba
52003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

Condition.
Shift Linkage
·
Damaged or incorrectly
adjusted ·
Inspect and repair as required. Verify transmission shift cable
adjustment; refer to Section 307 - 05 . Adjust transmission shift cable
as necessary. After repairing transmission shift cable, verify the digital
transmission range (TR) sensor is correctly adjusted. Adjust the
digital TR sensor as necessary. Incorrect Pressures
·
Low forward clutch
pressure, low line
pressure ·
Check pressure at line and forward clutch tap. Refer to Line Pressure
Chart for specification. If pressures are low, check the following
components: oil filter and seal assembly, main controls, pump
assembly, forward clutch assembly. Fluid Filter and Seal
Assembly
·
Plugged, damaged ·
Install a new filter and seal assembly. ·
Filter seal damaged Main Controls
·
3- 4 shift valve, main
regulator valve, manual
valve — stuck,
damaged ·
Inspect for damage. Repair as required. ·
Bolts not tightened to
specifications ·
Tighten bolts to specifications. ·
Gaskets damaged ·
Inspect gaskets for damage and install a new gasket. ·
2- 3 accumulator and
seals damaged ·
Inspect piston, seals and bore for damage. Repair as required. ·
Pressure regulator
valve ·
Inspect the diameter for wear. Pump Assembly
·
Bolts not tightened to
specifications ·
Tighten bolts to specifications. ·
Porosity/cross
leaks/ball missing or
leaking, plugged hole ·
Inspect for porosity and leaks. Repair as required. ·
No. 3 and No. 4 seal
rings damaged ·
Inspect seals for damage. Repair as required. ·
Gaskets damaged ·
Inspect for damage and install a new gasket. Forward Clutch
Assembly
·
Seals, piston damaged ·
Inspect seals for damage. Repair as required. ·
Check balls damaged,
missing, mislocated,
not seating correctly ·
Inspect for mislocation, poor seating, damage. Install a new cylinder
as required. ·
Friction elements
damaged or worn ·
Check for abnormal wear, damage. Repair as required. One-
Way Clutch
Assembly (Planetary) ·
Worn, damaged or
assembled incorrectly ·
Inspect for damage. Repair as required. Output Shaft Klj . 4 ba
312003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

·
Damaged ·
Inspect for damage. Install new components as required.
Engagement Concern: No Reverse Possible Component Reference/Action
202 —
ELECTRICAL ROUTINE ·
No Electrical Concerns 302 —
HYDRAULIC/MECHANICAL ROUTINE Fluid
·
Incorrect level ·
Adjust fluid to correct level. ·
Condition ·
Inspect condition of fluid. Shift Linkage
·
Damaged or incorrectly
adjusted ·
Inspect and repair as required. Verify transmission shift cable
adjustment; refer to Section 307 - 05 . Adjust transmission shift
cable as necessary. After repairing transmission shift cable, verify
that the digital TR sensor is correctly adjusted. Adjust the digital
TR sensor as necessary. Incorrect Pressures
·
Low reverse clutch
pressure, low reverse band
pressure, low line pressure ·
Check pressure at line pressure tap; refer to Line Pressure Chart
for specifications. If pressures are low, check the following
components: oil filter and seal assembly, main controls, reverse
servo, pump assembly, reverse clutch assembly. Fluid Filter and Seal
Assembly
·
Plugged, damaged ·
Install a new filter and seal assembly. Main Controls
·
No. 6 shuttle ball, manual
valve, main regulator valve,
1- 2 accumulator seals
stuck or damaged ·
Inspect for damage. Repair as required. ·
Loose bolts ·
Tighten bolts to specifications. ·
Gasket damaged ·
Inspect for damage and install a new gasket. Low/Reverse Servo
·
Seals (piston and cover)
damaged ·
Inspect for damage. Repair as required. ·
Servo cover retaining ring
damaged ·
Anchor pins (case)
damaged Pump Assembly
·
Loose bolts ·
Tighten bolts to specifications. ·
Porosity/cross leaks/ball
missing or leaking, plugged
hole ·
Inspect pump assembly. Install new as required. ·
Gasket damaged ·
Inspect for damage and install a new gasket. ·
No. 1 and 2 seal rings
damaged ·
Inspect for damage. Repair as required. Reverse Clutch Assembly Klj . 5 ba
312003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...