Ford Fusion: Rear Drive Axle/Differential / Rear Drive Axle and Differential. Diagnosis and Testing

Ford Fusion 2013–2020 Service Manual / Chassis / Driveline / Rear Drive Axle/Differential / Rear Drive Axle and Differential. Diagnosis and Testing

Preliminary Inspection

Visually inspect the housing, seals, and pinion flange for obvious signs of mechanical damage.

If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step

If the cause is not visually evident, verify the symptom and REFER to Symptom Chart: NVH.

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: NVH

Symptom Chart

Condition	Possible Sources	Actions
Axle howling or whine – front or rear axle	Axle lubricant low	CHECK the lubricant level. FILL the axle to specification.
	Axle housing damage	INSPECT the axle housing for damage. INSTALL a new axle housing if necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
	Damaged or worn differential and gear assembly	INSPECT the differential and gear assembly for damage. INSTALL a new axle assembly if necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Driveline clunk - loud clunk when shifting from REVERSE to DRIVE	Incorrect axle lubricant level	CHECK the lubricant level. FILL the axle to specification.
	Excessive backlash in the axle	CHECK for excessive axle backlash. INSPECT and INSTALL a new axle assembly as necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Driveline clunk — occurs as the vehicle starts to move forward following a stop	Loose rear axle mount	CHECK for loose bolts. TIGHTEN to specifications. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Grinding, popping or chattering – noise from the rear axle when the vehicle is turning	Incorrect or contaminated lubricant	CHECK the vehicle by driving in tight circles (5 clockwise, 5 counter clockwise). DRAIN and REFILL with the specified rear axle lubricant as necessary.
	Damaged RDU clutch - discs fused from twowheel or extended front to rear differentiation	TEST and INSTALL a new active torque coupling clutch as necessary. REFER to: Four-Wheel Drive Systems (308-07 Four-Wheel Drive Systems) .
	Damaged or worn differential (differential side gears and pinion gears)	INSPECT and INSTALL a new axle assembly as necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Grunting — normally associated with a shudder experienced during acceleration from a complete stop	Loose rear axle mount bolts or suspension fasteners	CHECK for loose bolts. TIGHTEN to specifications. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Howl – can occur at various speeds and driving conditions. Affected by acceleration and deceleration	Incorrect ring and pinion contact, incorrect bearing preload or gear damage	INSPECT and INSTALL a new axle assembly as necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Chuckle – heard at coast/ deceleration. Also described as knock	Incorrect ring and pinion contact or damaged teeth on the coast side of the ring and pinion	INSPECT and INSTALL a new axle assembly as necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Knock – noise occurs at various speeds. Not affected by acceleration or deceleration	Gear tooth damage to the driver side of the ring and pinion	INSPECT and INSTALL a new axle assembly as necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Scraping noise – a continuous low pitched noise starting at low speed	Worn or damaged pinion bearings	INSPECT and INSTALL a new axle assembly as necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
Driveline shudder – occurs during acceleration from a slow speed or stop	Rear drive axle assembly mispositioned	CHECK the axle mounts and the rear suspension for damage or wear. Repair as necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
	Loose rear axle bolts	CHECK the rear axle for loose bolts. TIGHTEN the bolts as necessary. REFER to: Axle Assembly (205-02 Rear Drive Axle/Differential, Removal and Installation).
	Driveline angles out of specification	CHECK for correct driveline angles.

Analysis of Leakage

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

A plugged Rear Drive Unit (RDU) housing vent can cause excessive pinion seal lip wear due to internal pressure buildup.

Verify the RDU lubricant level is 3-5 mm (1/8-3/16) below the bottom of the fill hole.

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

The drive pinion seal is not serviceable at this time.

Drive Pinion Nut

The drive pinion nut is not serviceable at this time.

Differential Seals

NOTICE: When installing shafts, do not allow splines to contact seals during installation or damage to the seals may occur.

Halfshaft pilot bearing housing seals are susceptible to the same types of damage as drive pinion seals if incorrectly installed. The seal bore must be clean and the lip handled carefully to avoid cutting or tearing it. The seal journal surface must be free of nicks, gouges and rough surface texture.

For information on differential seals,
REFER to: Rear Halfshaft Seal (205-02 Rear Drive Axle/Differential, Removal and Installation).

Specifications

Axle Assembly. Removal and Installation

Special Tool(s) / General Equipment Transmission Jack Materials Name Specification Motorcraft® SAE 80W-90 Premium Rear Axle LubricantXY-80W90-QL WSP-M2C197-A Removal Remove the rear halfshafts...

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Fuel Quality

Choosing the Right Fuel

Ford Fusion. Fuel Quality

Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87.