Lincoln Navigator Manuals

Lincoln Navigator: Front Drive Axle/Differential / Front Drive Axle. Diagnosis and Testing

Lincoln Navigator 2018-2025 Workshop Manual / Driveline / Front Drive Axle/Differential / Front Drive Axle. Diagnosis and Testing

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 A
Differential side gears/pinion gears are scored   GO to Pinpoint Test C
Front axle does not engage   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
Axle howling or whine   GO to Pinpoint Test G
Driveline clunk — occurs as the vehicle starts to move forward following a stop   GO to Pinpoint Test I
Grinding, popping or chattering – noise from the rear axle when the vehicle is turning   GO to Pinpoint Test J
Grunting — normally associated with a shudder experienced during acceleration from a complete stop   GO to Pinpoint Test K
Howl – can occur at various speeds and driving conditions. Affected by acceleration and deceleration   GO to Pinpoint Test L
Chuckle – heard at coast/ deceleration. Also described as knock   GO to Pinpoint Test M
Knock – noise occurs at various speeds. Not affected by acceleration or deceleration   GO to Pinpoint Test N
Scraping noise – a continuous low pitched noise starting at low speed   GO to Pinpoint Test O
Driveline shudder – occurs during acceleration from a slow speed or stop   GO to Pinpoint Test P

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 > Running > Overheats > Always GO to Pinpoint Test A
Start/Run/Move > Running > Overheats > Always GO to Pinpoint Test B
Start/Run/Move > Moving > No Engagement > Both (FWD and REV) GO to Pinpoint Test D
Start/Run/Move > Moving > 4 x 4 Function > Inoperative GO to Pinpoint Test D
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 > Visible Leak GO to Pinpoint Test G
Start/Run/Move > Fluids > Axle > Visible Leak GO to Pinpoint Test H
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 > Noise > Moving/Driving > Always GO to Pinpoint Test O
Start/Run/Move > Vibration > Moving/Driving > Intermittent GO to Pinpoint Test P

Pinpoint Tests


PINPOINT TEST A: AXLE OVERHEATING

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Axle lubricant low
  • Incorrect or contaminated lubricant type
  • Bearing preload adjusted too tight
  • Excessive gear wear
  • Incorrect ring gear backlash
A1 CHECK AXLE LUBRICANT LEVEL
  • Check the lubricant level.

Is the lubricant level low?
Yes Fill the axle to specification.
REFER to: Specifications (205-03 Front Drive Axle/Differential, Specifications).
No GO to A2

A2 CHECK AXLE CONDITION
  • Inspect the axle for damage.
  • Inspect axle lubricant.

Was damage found?
Yes Repair as necessary. Clean and Refill the axle to specification as necessary.
REFER to: Specifications (205-03 Front Drive Axle/Differential, Specifications).
No GO to A3

A3 INSPECT THE RING AND PINION GEAR
  • Check the ring and pinion for damage.

Does the ring and pinion have a wear pattern?
Yes Adjust the preload as necessary.
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
No GO to A4

A4 INSPECT ALL THE AXLE GEARS FOR WEAR OR DAMAGE
  • Inspect all the axle gears for wear or damage.

Was wear or damage found?
Yes Install new components as necessary.
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Disassembly and Assembly).
No GO to A5

A5 INSPECT THE RING GEAR FOR SCORING
  • Inspect the ring gear for scoring.

Was a wear pattern found on the ring and pinion?
Yes
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST B: BROKEN GEAR TEETH ON THE RING GEAR OR PINION

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, 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

  • Debris in axle
  • Overloading the vehicle
B1 INSPECT THE RING GEAR OR PINION GEARS FOR BROKEN GEAR TEETH
  • Inspect the ring gear or pinion gears for broken gear teeth.

Was wear or damage found?
Yes Install new components as necessary.
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Disassembly and Assembly).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST C: DIFFERENTIAL SIDE GEARS/PINION GEARS ARE SCORED

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, 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

  • Insufficient lubrication
  • Incorrect or contaminated lubricant
C1 CHECK AXLE LUBRICANT LEVEL AND CONDITION
  • Check the lubricant level.
  • Check the lubricant for contamination.

Is the lubricant level low or contaminated?
Yes
REFER to: Differential Fluid Level Check (205-03 Front Drive Axle/Differential, General Procedures).
No GO to C2

C2 INSPECT THE DIFFERENTIAL SIDE GEARS/PINION GEARS FOR SCORING
  • Inspect the differential side gears/pinion gears for scoring.

Was wear or damage found?
Yes Install new components as necessary.
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Disassembly and Assembly).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST D: FRONT AXLE DOES NOT ENGAGE

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Mode Switch
  • 4x4 control module
  • Differential
  • IWE
  • TCCM
  • Wiring
D1 CHECK THE ELD (ELECTRONIC LOCKING DIFFERENTIAL) DIAGNOSTIC TROUBLE CODES (DTCS)
  • Ignition ON.
  • Using a diagnostic scan tool, carry out the TCCM self-test.

Are there any DTC s present?
Yes
REFER to: DTC Chart and Pinpoint Tests - Vehicles With: 1-Speed Torque On Demand Transfer Case (307-07A Four-Wheel Drive Systems, Diagnosis and Testing).
REFER to: DTC Chart and Pinpoint Tests - Vehicles With: 2-Speed Torque On Demand Transfer Case (307-07A Four-Wheel Drive Systems, Diagnosis and Testing).
No The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.

PINPOINT TEST E: GRAY OR MILKY AXLE LUBRICANT IN LOW MILEAGE VEHICLE

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Damaged axle housing
  • Damaged axle vent
E1 INSPECT AXLE HOUSING AND VENT
  • Inspect axle housing and vent for damage or leaks.

Was any damage or leaks found?
Yes Repair as necessary.
No Refer to Axle Fluid Analysis in this section.

PINPOINT TEST F: LUBRICANT LEAKING FROM THE PINION SEAL, AXLE SHAFT OIL SEALS OR SUPPORT ARM TO THE HOUSING

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Vent
  • Damage in the seal contact area or dust slinger on the pinion flange dust shield
F1 INSPECT AXLE VENT
  • Inspect axle housing vent for blockage.

Was blockage found?
Yes Clean the axle housing vent.
No GO to F2

F2 INSPECT THE PINION SEAL AND DUST SLINGER
  • Inspect for damage to seal contact area or dust slinger.

Was any damage found?
Yes Install a new pinion flange and the pinion seal.
REFER to: Drive Pinion Flange and Seal (205-03 Front Drive Axle/Differential, Removal and Installation).
No The system is operating correctly at this time.

PINPOINT TEST G: AXLE HOWLING OR WHINE

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Axle lubricant low
  • Axle housing damage
  • Damaged, worn or incorrect ring and pinion gear contact
G1 CHECK THE LUBRICANT LEVEL
  • Check the lubricant level.

Is the lubricant level low?
Yes Fill the axle to specification.
REFER to: Specifications (205-03 Front Drive Axle/Differential, Specifications).
No GO to G2

G2 INSPECT AXLE HOUSING FOR DAMAGE
  • Inspect axle housing for damage.

Was any damage found?
Yes Install a new axle assembly as necessary.
REFER to: Axle Assembly (205-03 Front Drive Axle/Differential, Removal and Installation).
No GO to G3

G3 INSPECT RING AND PINION GEAR CONTACT
  • Inspect ring and pinion gear contact.

Was any damage found?
Yes Refer to Contact Pattern in this procedure or
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST H: DRIVELINE CLUNK- LOUD CLUNK WHEN SHIFTING FROM REVERSE TO DRIVE

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Axle lubricant level
  • Excessive backlash in the axle
H1 CHECK THE LUBRICATION LEVEL
  • Check the lubricant level.

Is the lubricant level low?
Yes Fill the axle to specification.
REFER to: Specifications (205-03 Front Drive Axle/Differential, Specifications).
No GO to H2

H2 CHECK FOR EXCESSIVE AXLE BACKLASH
  • Check for excessive axle backlash.

Is there excessive axle backlash?
Yes Adjust backlash as necessary.
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST I: DRIVELINE CLUNK- OCCURS AS THE VEHICLE STARTS TO MOVE FORWARD FOLLOWING A STOP

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Pinion gears
I1 INSPECT PINION GEARS
  • Inspect pinion gears.

Was any damage found?
Yes Replace as necessary.
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Disassembly and Assembly).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST J: GRINDING, POPPING OR CHATTERING- NOISE FROM THE REAR AXLE WHEN THE VEHICLE IS TURNING

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Damaged or worn differential
J1 INSPECT THE DIFFERENTIAL CARRIER AND THE COMPONENTS OF THE DIFFERENTIAL CARRIER
  • Inspect the differential carrier and the components of the differential carrier.

Was any damage found?
Yes Install a new differential carrier and/or differential carrier components as necessary.
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Removal and Installation).
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Disassembly and Assembly).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST K: GRUNTING- NORMALLY ASSOCIATED WITH A SHUDDER EXPERIENCED DURING ACCELERATION FROM A COMPLETE STOP

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Loose rear axle mount bolts
  • Loose suspension fasteners
K1 CHECK FOR LOOSE BOLTS
  • Check for loose bolts.

Are any bolts loose?
Yes Tighten to specifications.
REFER to: Axle Assembly (205-03 Front Drive Axle/Differential, Removal and Installation).
No The system is operating correctly at this time.

PINPOINT TEST L: HOWL- CAN OCCUR AT VARIOUS SPEEDS AND DRIVING CONDITIONS (AFFECTED BY ACCELERATION AND DECELERATION)

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Incorrect ring and pinion contact
  • Bearing preload
  • Gear damage
L1 INSPECT RING AND PINION, BEARING PRELOAD AND FOR GEAR DAMAGE
  • Inspect ring and pinion, bearing preload and for gear damage.

Was ring and pinion or bearing preload out of specification?
Yes Adjust as necessary.
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Removal and Installation).
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Disassembly and Assembly).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST M: CHUCKLE- HEARD AT COAST/DECELERATION. ALSO DESCRIBED AS KNOCK

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Incorrect ring and pinion contact
  • Damaged teeth on the coast side of the ring and pinion
M1 INSPECT RING AND PINION CONTACT AND FOR DAMAGED TEETH ON RING AND PINION
  • Inspect ring and pinion contact and for damaged teeth on ring and pinion.

Was any damage found?
Yes Adjust or install a new ring and pinion as necessary. Refer to Contact Pattern in this procedure, or
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST N: KNOCK- NOISE OCCURS AT VARIOUS SPEEDS (NOT AFFECTED BY ACCELERATION OR DECELERATION)

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Gear tooth damage to the driver side of the ring and pinion
N1 INSPECT FOR TOOTH DAMAGE ON RING AND PINION
  • Inspect for tooth damage on ring and pinion.

Was any damage found?
Yes Install a new ring and pinion as necessary.
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Removal and Installation).
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
REFER to: Differential Carrier (205-03 Front Drive Axle/Differential, Disassembly and Assembly).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST O: SCRAPING NOISE- A CONTINUOUS LOW PITCHED NOISE STARTING AT LOW SPEED

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Damaged pinion bearings
  • Worn pinion bearings
O1 INSPECT PINION BEARINGS
  • Inspect pinion bearings.

Was wear or damage found?
Yes Install new pinion bearings as necessary.
REFER to: Differential Ring Gear and Pinion (205-03 Front Drive Axle/Differential, Removal and Installation).
No Inspect the vehicle for any other symptoms related to the axle.

PINPOINT TEST P: DRIVELINE SHUDDER - OCCURS DURING ACCELERATION FROM A SLOW SPEED OR STOP

Normal Operation and Fault Conditions

REFER to: Front Drive Axle and Differential (205-03 Front Drive Axle/Differential, Description and Operation).

Possible Sources

  • Axle mispositioned
  • Loose axle bolts
  • Driveline angle
P1 CHECK THE AXLE MOUNTS AND THE REAR SUSPENSION FOR DAMAGE OR WEAR
  • Check the axle mounts and the rear suspension for damage or wear.

Was wear or damage found?
Yes Repair as necessary.
REFER to: Axle Assembly (205-03 Front Drive Axle/Differential, Removal and Installation).
No GO to P2

P2 CHECK THE REAR AXLE FOR LOOSE BOLTS
  • Check the rear axle for loose bolts.

Were any bolts loose?
Yes Tighten the bolts as necessary.
REFER to: Axle Assembly (205-03 Front Drive Axle/Differential, Removal and Installation).
No GO to P3

P3 CHECK FOR CORRECT DRIVELINE ANGLES
  • Check for correct driveline angles.
    REFER to: Driveshaft Angle Measurement (205-01 Driveshaft, General Procedures).

Are the driveline angles correct?
Yes Inspect the vehicle for any other symptoms related to the axle.
No Repair as necessary.


Analysis of Leakage

Clean up the leaking area enough to identify the exact source.

Test drive (after clean) to build up pressure and see seep and weep coming back or not.

A plugged front axle housing vent can cause excessive pinion seal lip wear due to internal pressure buildup.

If lubricant leakage, seepage or weepage observed then GO to Pinpoint Test F

Verify the differential lubricant level is at the correct level.
REFER to: Differential Fluid Level Check (205-03 Front Drive Axle/Differential, 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:

  • Damaged seal
  • Worn seal journal surface

A new drive pinion flange must be installed if any of these conditions exist.

  • Any damage to the seal bore (dings, dents, gouges or other imperfections) distorts the seal casing and allows leakage past the outer edge of the drive pinion seal.
  • The drive pinion seal can be torn, cut or gouged if it is not installed correctly. The spring that holds the drive pinion seal against the pinion flange may be knocked out and allow fluid to pass the lip.
  • Metal chips trapped at the sealing lip can cause oil leaks. These can cause a wear groove on the drive pinion flange and result in pinion seal wear.
  • When a seal leak occurs, install a new drive pinion seal and check the vent to make sure it is clean and free of foreign material.

Contact Pattern

In general, desirable ring gear tooth patterns must have the following characteristics:

  • Drive pattern on the drive side ring gear well centered on the tooth. There should be some clearance between the pattern and the top of the tooth.
  • Coast pattern on the coast side ring gear well centered on the tooth, but may be slightly toward the toe. There should be some clearance between the pattern and the top of the tooth.

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.

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