Diagnostic Routines

WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

DIAGNOSTIC ROUTINE - FLUID LOSS

Possible Component	Reference/Action
Vent	CLEAN the axle vent and vent hose.
Overfilled axle	CHECK the lubricant level for specific amount.
Fill plug	CLEAN the area around the plug. REMOVE the plug. APPLY pipe sealant and INSTALL the plug.
Halfshaft oil seal	INSTALL a new halfshaft oil seal.
Pinion seal	INSTALL a new pinion seal.
Differential housing cover	RESEAL the differential housing cover.

DIAGNOSTIC ROUTINE - NOISE LOUDER ON TURNS (SWEEPING)

Possible Component	Reference/Action
Wheel end bearing	CHECK the wheel end bearing for wear or damage. INSTALL a new bearing.

DIAGNOSTIC ROUTINE - NOISE (GROWL) IN TIGHT TURN, CONVENTIONAL DIFFERENTIAL

Possible Component	Reference/Action
Differential side gears and differential pinion gears	Disassemble the differential carrier. INSPECT the differential case assembly. INSTALL new side gears and differential pinion gears or case assembly.

DIAGNOSTIC ROUTINE - NOISE (CHATTER/SHUDDER) IN TIGHT TURNS, LIMITED SLIP DIFFERENTIAL

Possible Component	Reference/Action
Clutch pack	VERIFY the condition. With the vehicle in cold startup, MAKE SURE that the vehicle is in 2WD, to isolate the rear axle. TURN the wheel fully right (or fully left) and then ACCELERATE the vehicle. If the condition is verified to be in the rear axle, REMOVE and INSTALL new clutch packs.

DIAGNOSTIC ROUTINE - NOISE (WHINE) IN ALL OR MORE THAN ONE DRIVE MODES

Possible Component	Reference/Action
Axle ring and pinion	REMOVE and INSTALL a new gear set and bearings.

DIAGNOSTIC ROUTINE - NOISE (TICK/CLICK) IN ALL OR MORE THAN ONE DRIVE MODES

Possible Component	Reference/Action
Axle ring and pinion	REMOVE and INSTALL a new ring gear, pinion and bearings.

DIAGNOSTIC ROUTINE - NOISE (HOWL/MOAN) IN ALL OR MORE THAN ONE DRIVE MODES

Possible Component	Reference/Action
Axle bearings	INSPECT differential and pinion bearings. INSTALL new bearings.

DIAGNOSTIC ROUTINE - NOISE (CLUNK) ON CHANGES IN SPEED OR DIRECTION OF POWER

Possible Component	Reference/Action
Axle and Pinion System	Measure total backlash. If end play and total backlash are within specification, INSTALL a new differential case assembly.
Differential pinion shaft	INSTALL a new differential pinion shaft and pin.
Pinion Bearings	INSTALL new pinion and differential bearings and bearing cups.

DIAGNOSTIC ROUTINE - FRONT AXLE WILL NOT ENGAGE/DISENGAGE

Possible Component	Reference/Action
Mode switch Wiring Shift motor	REFER to FOUR WHEEL DRIVE SYSTEMS .

DIAGNOSTIC ROUTINE - VIBRATION

Possible Component	Reference/Action
For additional information on driveline vibration, REFER to NOISE, VIBRATION & HARSHNESS .