Unfortunately, this is a somewhat common problem. Ford has issued several
Techinical Service Bulletins related to rear end noise. Unless you have an
extended warranty, this is something you will ahve to pay to change.

TSB 05-23-3 11/28/05

REAR AXLE NOISE REPAIR\

FORD:
1997-2005 Expedition, F-150
2002-2005 Explorer
LINCOLN:
1998-2005 Navigator
2003-2005 Aviator
MERCURY:
2002-2005 Mountaineer

This article supersedes TSB 05-12-6 to update the Service Kit and Service
Procedure information.

ISSUE

Some vehicles may exhibit an axle whine or hum during acceleration,
deceleration and/or cruise.

ACTION
An axle repair kit has been developed which incorporates most parts required
for a comprehensive axle repair. The kit should be used instead of
installing a complete axle assembly to repair an axle whine/hum. Replace
Ring and Pinion with Axle Kit and Components.

NOTE REFER TO THE "DIFFERENTIAL RING AND PINION" IN-VEHICLE REPAIR PROCEDURE
IN THE ONLINE WORKSHOP MANUAL SECTION 205-00, FOR THE LATEST AXLE DIAGNOSIS
AND REPAIR PROCEDURES.

NOTE FOR 1999 AND PRIOR MODEL YEAR VEHICLES, USE THE 2000 MODEL YEAR
WORKSHOP MANUAL.

NOTE WHEN SERVICING THE REAR AXLE ON ANY 2002-2004 F-150, EXPEDITION,
NAVIGATOR, EXPLORER OR MOUNTAINEER BUILT BEFORE 3/30/2004, IF FLUID
REPLACEMENT IS REQUIRED, REPLACE THE ORIGINAL FUEL EFFICIENT HIGH
PERFORMANCE (FEHP) SAE 75W-90 REAR AXLE LUBRICANT WITH SAE 75W-140 HIGH
PERFORMANCE SYNTHETIC REAR AXLE LUBRICANT. WHEN THE FLUID TYPE IS CHANGED,
REPLACE THE CURRENT "FEHP" METAL TAG WITH A NEW "75W-140" TAG
(F3TZ-4121-AA). IN ADDITION, REMOVE OR BLOCK-OUT THE FEHP REFERENCE ON THE
MULTI-COLORED LABEL LOCATED ON THE RIGHT SIDE AXLE TUBE. IF THE AXLE IS A
LIMITED-SLIP MODEL, USE XL3 ADDITIVE FRICTION MODIFIER IN THE QUANTITY
RECOMMENDED BY THE WORKSHOP MANUAL.

KIT ORDERING: REFER TO THE VEHICLE AXLE  TAG FOR AXLE RATIO IDENTIFICATION

- 5L3Z-4209-A = (8.8-Inch Ring Gear/3.31 ratio) (1997-2005 F-150)
- 5L3Z-4209-B = (8.8-Inch Ring Gear/3.55 ratio) (1997-2005 F-150, 2002-2005
Explorer/Mountaineer/Aviator)
- 5L3Z-4209-C = (8.8-Inch Ring Gear/3.73 ratio) (1997-2005 F-150, 2002-2005
Explorer/Mountaineer/Aviator, 2003-2004 Expedition/Navigator)
- 5L3Z-4209-D = (9.75-Inch Ring Gear/3.31 ratio) (1997-2005 F-150, 2005
Expedition/Navigator, 1997-2002 Expedition/Navigator)
- 5L3Z-4209-E = (9.75-Inch Ring Gear/3.55 ratio) (1997-2005 F-150, 1997-2002
Expedition/Navigator)
- 5L3Z-4209-F = (9.75-Inch Ring Gear/3.73 ratio) (1997-2005 F-150, 1997-2005
Expedition/Navigator)

NOTE 9.75 REAR AXLE HOUSINGS WERE REDESIGNED IN MID-1999, INCREASING FRONT
PINION BEARING SIZE. REPLACING RING & PINIONS IN AN OLD-STYLE AXLE ASSEMBLY
WILL REQUIRE INSTALLATION OF SPACER P/N YL3Z4662-CA. SPACER IS TO BE
INSTALLED BETWEEN INNER PINION BEARING AND COLLAPSIBLE SPACER.

THE AXLE SERVICE KITS INCLUDE THE FOLLOWING COMPONENTS:

- 4630 - Head Bearing
- 4628 - Head Bearing Cup
- 4676 - Pinion Seal
- 386989-S2 - Washer (Slinger)
- 4621 - Tail Bearing
- 4616 - Tail Bearing Cup
- 4222 - Differential Bearing Cups
- 4221 - Differential Bearings
- 4209 - Gear Set (includes pinion shims, pinion nut and crush spacer)
- 4209 - Instruction Sheet

NOTE THE KIT DOES NOT INCLUDE THE FOLLOWING ITEMS. SOME OR ALL OF THESE
ITEMS WILL BE REQUIRED TO COMPLETE THE AXLE SERVICE, DEPENDING ON AXLE
APPLICATION/STYLE.

ORDER AS NEEDED:

NOTE REUSE OF RING GEAR BOLTS, CARRIER BEARING CAP BOLTS AND DIFFERENTIAL
SLAVE PIN RETAINING BOLT REQUIRES CLEANING OF THREADS AND INSTALLATION OF
TA-27 STUD AND BEARING MOUNT RETAINING COMPOUND & SEALANT.

- YL3Z-4662-CA - Pinion Bearing Spacer for 1997-1998 9.75 axles
- XG-14 - Gear Marking Compound
- 4067 - Differential Shims 0.241" to 0.307"
- SAE XY-75W140-QL - High Performance Synthetic Rear Axle Lubricant
- XL-3 - Additive Friction Modifier (Limited Slip Axles Only)
- 205-506 - Seal Protectors (Rotunda Tool)
- W710084-5439 - Wheel End Nuts
- 390266-S199 - Differential Slave Pin Bolt (9.75" axles)
- 387426-S100 - Differential Slave Pin Bolt (8.8" axles)
- 4B422 - Axle Circlips
- ZC-21 - Metal Surface Cleaner
- TA-29 - Ultra Silicone Sealant
- TA-27 - Stud and Bearing Mount Retaining Compound and Sealer
- F3TZ-4121-AA - Fluid Tag (REQUIRED IF FLUID TYPE IS CHANGED FROM FEHP
DURING REPAIR)

WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty
Coverage
OPERATION       DESCRIPTION                     TIME

052303A         1997-2002 Expedition,           4.7 Hrs.
                       1998-2002 Navigator,
                       1997-2004 F-150 Heritage,
                       2004-2005 F-150: Rear
                       axle Noise Repair
                       (Includes Time For Road
                       Test To Verify Concern
                       (Beam Axle)) (Do Not Use
                      With 4205A Or 4205A4)

052303A         2003-2005 Expedition:           5.8 Hrs.
                       Rear Axle Noise Repair
                       (Includes Time For Road
                       Test To Verify Concern (lrs
                       Axle)) (Do Not Use With
                       4010D Or 4010D4)

052303A         2003-2005                              5.9 Hrs.
                       Expedition/Navigator With
                      Air Suspension: Rear Axle
                      Noise Repair (Includes
                     Time For Road Test To
                     Verify Concern (lrs Axle))
                     (Do Not Use With 4010D
                     Or 4010D4)

052303A         2002-2005                       6.6 Hrs.
                       Explorer/Mountaineer,
                       2003-2005 Aviator: Rear
                       Axle Noise Repair
                       (Includes Time For Road
                        Test To Verify Concern (lrs
                       Axle)) (Do Not Use With
                       4010D Or 4010D4)

DEALER CODINGCONDITION BASIC PART NO.CODE 420914

OASIS CODES: 509000, 590000, 597997, 702000, 702200, 703200, 703300, 703400,
790000