Symptom Chart(s)
Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).
Symptom Chart - Differential
Symptom Chart - Differential
Condition | Actions |
---|---|
Axle overheating | GO to Pinpoint Test A |
Broken gear teeth on the ring gear or pinion | GO to Pinpoint Test B |
Differential side gears/pinion gears are scored | GO to Pinpoint Test C |
eLSD does not engage in snow, mud or on ice | GO to Pinpoint Test D |
Gray or milky axle lubricant in low mileage vehicles | GO to Pinpoint Test E |
Lubricant leaking from the pinion seal, axle shaft oil seals or support arm to the housing | GO to Pinpoint Test F |
Symptom Chart: NVH
Symptom Chart
Condition | Actions |
---|---|
Rotational noise from center of axle including howl, whine, scraping, grinding, whistle, moan, or roar | GO to Pinpoint Test G |
Driveline clunk — occurs as the vehicle starts to move forward following a stop | GO to Pinpoint Test H |
Grinding, popping or chattering – noise from the rear axle when the vehicle is turning | GO to Pinpoint Test I |
Grunting — normally associated with a shudder experienced during acceleration from a complete stop | GO to Pinpoint Test J |
Rotational noise from outer ends of axle including howl, whine, grinding, moan, or roar that change in pitch when cornering | GO to Pinpoint Test K |
Chuckle – heard at coast/ deceleration. Also described as knock | GO to Pinpoint Test L |
Knock – noise occurs at various speeds. Not affected by acceleration or deceleration | GO to Pinpoint Test M |
Scraping noise – a continuous low pitched noise starting at low speed | GO to Pinpoint Test N |
Driveline shudder – occurs during acceleration from a slow speed or stop | GO to Pinpoint Test O |
Global Customer Symptom Code (GCSC) Chart
Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).
Symptom | Action |
---|---|
Start/Run/Move > Fluids > Axle > Consumption | GO to Pinpoint Test A |
Start/Run/Move > Fluids > Axle > Consumption | GO to Pinpoint Test B |
Start/Run/Move > Fluids > Axle > Consumption | GO to Pinpoint Test C |
Start/Run/Move > Fluids > Axle > Visible Leak | GO to Pinpoint Test A |
Start/Run/Move > Fluids > Axle > Visible Leak | GO to Pinpoint Test B |
Start/Run/Move > Fluids > Axle > Visible Leak | GO to Pinpoint Test C |
Start/Run/Move > Fluids > Axle > Visible Leak | GO to Pinpoint Test F |
Start/Run/Move > Fluids > Axle > Contamination | GO to Pinpoint Test A |
Start/Run/Move > Fluids > Axle > Contamination | GO to Pinpoint Test B |
Start/Run/Move > Fluids > Axle > Contamination | GO to Pinpoint Test C |
Start/Run/Move > Fluids > Axle > Contamination | GO to Pinpoint Test E |
Start/Run/Move > Noise > Moving/Driving > Always | GO to Pinpoint Test G |
Start/Run/Move > Noise > Moving/Driving > Always | GO to Pinpoint Test H |
Start/Run/Move > Noise > Moving/Driving > Always | GO to Pinpoint Test I |
Start/Run/Move > Noise > Moving/Driving > Always | GO to Pinpoint Test J |
Start/Run/Move > Noise > Moving/Driving > Always | GO to Pinpoint Test K |
Start/Run/Move > Noise > Moving/Driving > Always | GO to Pinpoint Test L |
Start/Run/Move > Noise > Moving/Driving > Always | GO to Pinpoint Test M |
Start/Run/Move > Noise > Moving/Driving > Always | GO to Pinpoint Test N |
Start/Run/Move > Vibration > Moving/Driving > Intermittent | GO to Pinpoint Test O |
Pinpoint Tests
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
A1 CHECK AXLE LUBRICANT LEVEL | ||||
Is the lubricant level low?
|
||||
A2 CHECK AXLE CONDITION | ||||
Was damage found?
|
||||
A3 INSPECT THE RING AND PINION GEAR | ||||
Does the ring and pinion have a wear pattern?
|
||||
A4 INSPECT ALL THE AXLE GEARS FOR WEAR OR DAMAGE | ||||
Was wear or damage found?
|
||||
A5 INSPECT THE RING GEAR FOR SCORING | ||||
Was a wear pattern found on the ring and pinion?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Broken gear teeth on the ring or pinion gear can be the result of vehicle overloading, insufficient axle lubricant, contaminated axle lubricant or incorrect axle lubricant. Possible Sources
|
||||
B1 INSPECT THE RING GEAR OR PINION GEARS FOR BROKEN GEAR TEETH | ||||
Was wear or damage found?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Scoring on the pinion gear or side gears can be the result of insufficient axle lubricant, contaminated axle lubricant, or incorrect axle lubricant. Possible Sources
|
||||
C1 CHECK AXLE LUBRICANT LEVEL AND CONDITION | ||||
Is the lubricant level low or contaminated?
|
||||
C2 INSPECT THE DIFFERENTIAL SIDE GEARS/PINION GEARS FOR SCORING | ||||
Was wear or damage found?
|
D1 CHECK THE ELSD (ELECTRONIC LIMITED-SLIP DIFFERENTIAL) DTC (DIAGNOSTIC TROUBLE CODE)S | ||||
Are there ant DTC s present?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
E1 INSPECT AXLE HOUSING AND VENT | ||||
Was any damage or leaks found?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
F1 INSPECT AXLE VENT | ||||
Was blockage found?
|
||||
F2 INSPECT THE PINION SEAL AND DUST SLINGER | ||||
Was any damage found?
|
Normal Operation and Fault Conditions All gearsets and roller bearings, including those found in the axle, generate some noise during normal operation. Some normal noises may be perceived as severe when the vehicle is raised on a hoist and the listener is closer to the axle. A worn ring and pinion gearset can produce a whine or whistle type of noise. The noise comes in at certain vehicle speed. The noise will peak and fade away usually within a 5-10 MPH (8-16 km/h) range. The noise may be present in one or more drive conditions: tip in / tip out / coast / cruise. Worn pinion bearings can produce a scraping noise. This noise will be a continuous low pitched noise starting at low speeds. Worn differential bearings can produce a growling or grinding noise that increases with speed and load. Gear tooth damage on the drive side of the ring or pinion can cause a knock noise. This noise can occur at various speeds and is not affected by acceleration or deceleration. Excessive backlash can cause a driveline clunk that occurs as the vehicle starts to move forward following a stop. Excessive backlash can also cause a chuckle or knock type of noise that will be heard during coast and deceleration. Excessive backlash is caused by ring and pinion gear wear. Gear tooth damage on the coast side of the ring or pinion can cause a chuckle or knock type of noise that will be heard during coast and deceleration. As the bearings or gears wear, metallic particles are shed and distributed into the axle fluid. This metallic contamination can cause the other components in the axle to fail. The ring and pinion gears, pinion bearings (included in -4209- kit), differential bearings (-4221-), and differential bearing cups (-4222-) should be replaced when repairing an axle for the noise concerns described in this diagnostic test. Possible Sources
|
||||
G1 COMPARE TO LIKE UNIT | ||||
Is the noise in the subject vehicle similar to the noise from the comparable vehicle?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
H1 INSPECT PINION GEARS | ||||
Was any damage found?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
I1 INSPECT THE DIFFERENTIAL CARRIER AND THE COMPONENTS OF THE DIFFERENTIAL CARRIER | ||||
Was any damage found?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
J1 CHECK FOR LOOSE BOLTS | ||||
Are any bolts loose?
|
Normal Operation and Fault Conditions All roller bearings, including those found in the rear axle, generate some noise during normal operation. Some normal noises may be perceived as severe when the vehicle is raised on a hoist and the listener is closer to the rear axle. Worn outer wheel bearings can produce a howl, whine, grinding, moan, or roar that change in pitch when cornering. Possible Sources
|
||||
K1 COMPARE TO LIKE UNIT | ||||
Is the noise in the subject vehicle similar to the noise from the comparable vehicle?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
L1 INSPECT RING AND PINION CONTACT AND FOR DAMAGED TEETH ON RING AND PINION | ||||
Was any damage found?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
M1 INSPECT FOR TOOTH DAMAGE ON RING AND PINION | ||||
Was any damage found?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
N1 INSPECT PINION BEARINGS | ||||
Was wear or damage found?
|
Normal Operation and Fault Conditions
REFER to: Rear Drive Axle and Differential (205-02 Rear Drive
Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Description
and Operation). Possible Sources
|
||||
O1 CHECK THE AXLE MOUNTS AND THE REAR SUSPENSION FOR DAMAGE OR WEAR | ||||
Was wear or damage found?
|
||||
O2 CHECK THE REAR AXLE FOR LOOSE BOLTS | ||||
Were any bolts loose?
|
||||
O3 CHECK FOR CORRECT DRIVELINE ANGLES | ||||
Are the driveline angles correct?
|
Axle Fluid Analysis
The appearance of milky or gray axle fluid in early mileage axles is a result of white marking compound used at the assembly plant to verify gear mesh contact pattern. The marking compound within the fluid will darken some over time. The milky fluid appearance will diminish and cause no harm and does not require a fluid change.
Analysis of Leakage
Clean up the leaking area enough to identify the exact source.
A plugged Rear axle housing vent can cause excessive pinion seal lip wear due to internal pressure buildup.
Verify the differential lubricant level is at the correct level.
REFER
to: Differential Fluid Level Check (205-02 Rear Drive Axle/Differential
- Vehicles With: Ford 9.75 Inch Ring Gear, General Procedures).
Axle Vent
A plugged vent will cause excessive seal lip wear due to internal pressure buildup. If a leak occurs, check the vent. If the vent cannot be cleared, install a new vent.
Drive Pinion Seal
Leaks at the drive pinion seal originate from the following causes:
A new drive pinion flange must be installed if any of these conditions exist.
Contact Pattern
In general, desirable ring gear tooth patterns must have the following characteristics:
Acceptable ring gear tooth patterns for all axles.
Correct backlash with a thicker pinion position shim required.
Correct backlash with a thinner pinion position shim required.
Pinion position correct. Decrease backlash.
Pinion position correct. Increase backlash.
This document provides critical diagnostic knowledge required for successful repair outcomes. It identifies technical competencies expected by users of this manual.
Ford Diagnostic Assumptions
Ford diagnostics assume the vehicle concern described by the test title is currently present. Exceptions to this rule are noted in each test. Do not replace modules or other components as directed by a diagnostic if the concern is not present at the time of testing.