Symptom Chart: Power Transfer Unit (PTU)
Diagnostics in this information assume a certain skill level and knowledge of Ford-specific diagnostic practices. REFER to ENGINE CONTROLS - DIAGNOSTIC METHODS (EXCEPT DIESEL & HYBRID) for information regarding Ford-specific diagnostic practices.
Preliminary Inspections
Note. For concerns with the AWD system, REFER to SYMPTOM CHART(S) : Four Wheel Drive (4WD) Systems.
- Verify the customer concern.
- Inspect for obvious signs of mechanical damage. PTU Halfshafts and CV joints Driveshaft and U-Joint Wheel/tire size and brand Tire pressure
- Matching tire size and brand.
- If the cause is not visually evident, verify the symptom and GO to «Symptom Chart»(ref-517578-S26206112182012121200000) .
| 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 transaxle while in NEUTRAL, or in some gears and not in others, REMOVE and REPAIR the transaxle. REFER to SYMPTOM CHART . If there is noise in all gears, INSTALL a new PTU. REFER to Power Transfer Unit (PTU) . | |
| Leaking fluid from the PTU vent | PTU overfilled | REFER to Leakage Inspection . |
| Leaking automatic transmission fluid | PTU intermediate shaft seal PTU compression seal | REFER to Leakage Inspection . |
| Leaking gear lubricant from the seals | The vent on top of the PTU is plugged | INSTALL a new PTU. REFER to Power Transfer Unit (PTU) . |
| Damaged seals | REFER to Leakage Inspection . | |
| Vehicle has no or inadequate torque at rear wheels | Rear axle | REFER to REAR DRIVE AXLE-DIFFERENTIAL - Overview. |
| 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 SYMPTOM CHART: TIRE WEAR . |
| Brake system | REFER to SYMPTOM CHART: BRAKE SYSTEM . | |
| Wheel bearings | REFER to SYMPTOM CHART: SUSPENSION SYSTEM . | |
| Halfshafts | REFER to SYMPTOM CHART: NVH . | |
| Wheel speed sensor(s) | REFER to SYMPTOM CHART: VEHICLE DYNAMIC SYSTEMS . | |
| ABS module | REFER to SYMPTOM CHART: VEHICLE DYNAMIC SYSTEMS . |
SYMPTOM CHART
Component Test
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.
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 can be felt by running a finger nail across it where 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.
Scheme 1
Scheme 2
- Inspect the RH side of the PTU for leaks. If no leaks are found, GO to Step 2. NOTE: Remove and replace leaking seals using the information found in the Intermediate Shaft Seal and Deflector or Cover Seal replacement procedure in this information. The specified tools called out in this procedure allow seal replacement without causing damage to the PTU casing/drive gear. If the leak is red automatic transmission fluid, replace the PTU intermediate shaft seal located inside the bore of the PTU shaft, behind the deflector. REFER to «Intermediate Shaft Seal and Deflector»(ref-517578-S31678000092012121200000) . If the leak is brown/black gear lube, replace the PTU larger cover seal located on the PTU cover, behind the deflector. REFER to «Cover Seal»(ref-517578-S37099576332012121200000) . Item Service Part Number Description 1 7H459 Intermediate shaft seal (part of kit 7H459) 2 7H459 Alignment washer (part of kit 7H459) 3 7H459 Cover seal (part of kit 7H459) 4 7H459 Seal deflector (part of kit 7H459) Inspect the LH side of the PTU for leaks. If the leak is red automatic transmission fluid, replace the compression seal located between the PTU and transmission. REFER to «Power Transfer Unit (PTU)»(ref-517578-S28506350842012121200000) . If the leak is brown/black and venting fluid from the top of the PTU, the PTU is overfilled due to the input shaft seals leaking red automatic transmission fluid into the PTU. Replace the input shaft seals, REFER to «Input Shaft Seal»(ref-517578-S20323641122012121200000) . Item Service Part Number Description 1 7086 PTU-to-transaxle compression seal 2 - Transfer case drive gear seal (7H469) 3 - Transfer case drive gear seal (7H469)