Preliminary Inspections

WARNING: This page is about a different car, the 2013 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: For concerns with the AWD system, REFER to FOUR WHEEL DRIVE (4WD) SYSTEMS - SYMPTOM CHART .

Verify the customer concern.
Inspect for obvious signs of mechanical damage.
- PTU
- Halfshafts and CV joints
- Driveshaft and Universal Joint (U-Joint)
- Wheel/tire size and brand
- Tire pressure
NOTE: The PTU may leak different color fluids, red for automatic transmission fluid and brown/black gear lube for PTU fluid. The PTU seals prevent these types of fluids from leaking externally. It is important to note which color of fluid is leaking to determine the most appropriate service procedure.

Inspect for obvious leaks.
- Vent hose
- Intermediate shaft seal
- Cover seal
- Output shaft seal
- Mating surface of PTU and transaxle
Matching tire size and brand.
If the cause is not visually evident, verify the symptom and GO to Symptom Chart.

SYMPTOM CHART PTU

SYMPTOM DESCRIPTION - PTU

Condition	Possible Sources	Actions
The PTU makes noise	Tire inflation pressure Tire and wheel size	VERIFY all tires and wheels are the same size and brand and the inflation pressures are correct.
	Fluid level	FILL with the correct type and amount of lubricant. Refer to POWER TRANSFER UNIT (PTU) DRAINING AND FILLING .
	Internal components	OPERATE the vehicle in all gears. If there is noise in the transmission while in NEUTRAL, or in some gears and not in others, REMOVE and REPAIR the transmission. REFER to AUTOMATIC TRANSMISSION - SYMPTOM CHART . If there is noise in all gears, CONFIRM with chassis ears the noise is coming from the PTU . INSTALL a new PTU as necessary. Refer to POWER TRANSFER UNIT (PTU) .
Leaking fluid from the PTU vent	PTU overfilled	VERIFY fluid level. Refer to POWER TRANSFER UNIT (PTU) DRAINING AND FILLING .
	PTU overfilled and transmission fluid is low.	INSTALL new compression seal, intermediate shaft seal, deflector, and alignment washer. Refer to INPUT SHAFT SEAL , and INTERMEDIATE SHAFT SEAL AND DEFLECTOR . DRAIN and REFILL the PTU . Refer to POWER TRANSFER UNIT (PTU) DRAINING AND FILLING .
	PTU vent hose is disconnected or missing	CONNECT the PTU vent hose or INSTALL a new PTU vent hose as necessary.
Leaking automatic transmission fluid (Red fluid)	Damaged or worn PTU intermediate shaft seal	INSTALL a new intermediate shaft seal, deflector, and alignment washer. Refer to INTERMEDIATE SHAFT SEAL AND DEFLECTOR .
Leaking automatic transmission fluid (Red fluid)	Damaged or worn PTU compression seal	INSTALL a new compression seal, intermediate shaft seal, deflector, and alignment washer. Refer to POWER TRANSFER UNIT (PTU) , and INTERMEDIATE SHAFT SEAL AND DEFLECTOR .
Leaking gear lubricant from the seals (Brown fluid)	Damaged cover seal	INSTALL a new PTU cover seal. Refer to COVER SEAL .
	Damaged pinion seal and/or pinion flange seal mating surface	INSTALL a new pinion seal and pinion flange as needed. Refer to OUTPUT SHAFT SEAL .
	The vent on top of the PTU is plugged (vent hose equipped)	INSTALL a new PTU vent hose.
	The vent on top of the PTU is plugged (jiggle cap equipped)	Pressurize PTU thru the fill plug to verify. Refer to, Power Transfer Unit (PTU) Draining and Filling .
Vehicle has no or inadequate torque at rear wheels	Rear axle	REFER to REAR DRIVE AXLE AND DIFFERENTIAL , Overview.
Vehicle has no or inadequate torque at rear wheels	PTU mechanical failure	INSTALL a new PTU . Refer to POWER TRANSFER UNIT (PTU) .
Vehicle binds in a turn or resists turning/pulsates or shudders in a straight line	Wheels/tires	REFER to WHEELS AND TIRES .
	Brake system	REFER to BRAKE SYSTEM - SYMPTOM CHART - BRAKE SYSTEM .
	Wheel bearings	REFER to SUSPENSION SYSTEM, SYMPTOM CHART: SUSPENSION SYSTEM .
	Halfshafts	REFER to DRIVELINE SYSTEM - SYMPTOM CHART: NVH .
	Wheel speed sensor(s)	REFER to ANTI-LOCK BRAKE SYSTEM (ABS) AND STABILITY CONTROL - SYMPTOM CHART: VEHICLE DYNAMIC SYSTEMS .
	ABS module	REFER to ANTI-LOCK BRAKE SYSTEM (ABS) AND STABILITY CONTROL - SYMPTOM CHART: VEHICLE DYNAMIC SYSTEMS .