Symptom Chart: Notes

Diagnostics in this service information assume a certain skill level and knowledge of Ford-specific diagnostic practices. REFER to: Diagnostic Methods .

In most circumstances the PCM sets a DTC to help guide with diagnostics. Refer to the DTC Chart before using the Symptom Chart. The Condition column lists the vehicle condition. The Possible Sources column lists a detailed vehicle condition. The Action column lists the action to be performed to determine the cause of the condition. Each action lists the components that can cause the system and the individual components in that system. The components are listed in order of disassembly. Use the list of components and the required action to focus on disassembly inspections for the root cause of the concern.

Symptom	Possible Sources	Action
The power transfer unit makes noise	Tire inflation pressure Tire and wheel size Fluid level Internal components	MAKE SURE all tires and wheels are the same size and brand and the inflation pressures are correct. FILL with the correct type and amount of lubricant. OPERATE the vehicle in all gears. If there is noise in the transmission in NEUTRAL, or in some gears and not in others, REMOVE and REPAIR the transmission. REFER to: Transmission - 6F50/6F55. If there is noise in all gears, INSTALL a new power transfer unit. REFER to: Power Transfer Unit .
Leaking fluid from the power transfer unit vent	Power transfer unit is over filled	REFER to: Power Transfer Unit Fluid Level Check .
Leaking automatic transmission fluid	Power transfer unit intermediate shaft seal Power transfer unit compression seal	REFER to Analysis of Leakage .
Leaking gear lubricant from the seals	The power transfer unit vent is plugged (located on top of the power transfer unit) Damaged seals	INSTALL a new the power transfer unit vent tube. REFER to: Power Transfer Unit Vent . REPLACE the leaking seal. REFER to: Power Transfer Unit Input Shaft Seal . REFER to: Intermediate Shaft Seal . REFER to: Power Transfer Unit Rear Seal .
Vehicle has no or inadequate torque at rear wheels	Rear axle Power transfer unit mechanical failure	REFER to: Rear Drive Axle and Differential . REFER to: Power Transfer Unit .
Vehicle binds in a turn or resists turning/pulsates or shudders in a straight line	Wheels/tires Brake system Wheel bearings Halfshafts ABS system	REFER to: WHEELS AND TIRES . REFER to: Brake System . REFER to: Suspension System . REFER to: Front Drive Halfshafts . REFER to: ANTI-LOCK BRAKE SYSTEM (ABS) AND STABILITY CONTROL .
Loss of AWD function or partial AWD function	Power transfer unit overheating	INSPECT the duct that cools the power transfer unit sump is free and clear of debris.

NOTE: Inspection of the seal's mating journal should be performed every time a seal is replaced. The mating part/journal should be replaced if it has any of the following conditions: Radial wear groove that is felt by running a finger nail across where the seal lip runs. Scratches, pitting, galling, nicks or other shaft damage under or near where the seal lip runs. Discoloration or coked oil on the shaft where the seal lip runs. Shaft corrosion under or near where the seal lip runs. Sharp edges or burrs on the shaft lead in chamfer. NEVER use emery cloth on journal finishes, replace the part.