Symptom Chart
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 appropriate 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 |
|---|---|---|
| PTU Bearing noise during Disconnected mode | Fluid level PTU Input shaft support bearings |
FILL with the correct type and amount of lubricant. REFER to: Power Transfer Unit Fluid Level Check . REMOVE PTU, DISASSEMBLE and INSPECT input shaft bearings. REFER to: Power Transfer Unit Input Shaft Seal LH - 8-Speed Automatic Transmission - 8F35 . |
| PTU Bearing noise during Connected Mode - Either with or without RDU activation. | Fluid level PTU Ring gear shaft bearings PTU pinion gear / output shaft bearings |
FILL with the correct type and amount of lubricant. REFER to: Power Transfer Unit Fluid Level Check . REMOVE PTU, DISASSEMBLE and INSPECT input shaft bearings. REFER to: Power Transfer Unit Input Shaft Seal LH - 8-Speed Automatic Transmission - 8F35 . |
| Ratcheting or clicking type noise during Connecting or Disconnecting modes. | PTU input shaft dog clutch teeth worn or damaged PTU dog clutch collar teeth worn or damaged |
REMOVE PTU, DISASSEMBLE and INSPECT input shaft bearings. REFER to: Power Transfer Unit Input Shaft Seal LH - 8-Speed Automatic Transmission - 8F35 . |
| No torque available at the rear drive shaft / Driveshaft does not rotate in Connected Mode | Shift fork worn or broken Connecting sleeve to input shaft splines worn or damaged Dog clutch worn or damaged Ring and pinion teeth worn or broken |
REMOVE and INSPECT PTU Actuator Motor. REFER to: Power Transfer Unit Actuator Motor . REMOVE PTU and INSPECT connecting sleeve, dog clutch, and gears. REFER to: Power Transfer Unit Input Shaft Seal LH - 8-Speed Automatic Transmission - 8F35 . |
| Leaking automatic transmission fluid from right hand side | Power transfer unit intermediate shaft seal | INSTALL a new intermediate shaft. REFER to: Intermediate Shaft . |
| Leaking automatic transmission fluid from left hand side | Transmission right hand differential seal and PTU to transmission compression seal | INSTALL new seals. REFER to: Halfshaft Seal RH - FWD . |
| Leaking gear lubricant from right hand side | Power transfer unit input shaft seal - RH and intermediate shaft bearing to PTU O-Ring | INSTALL new seals. REFER to: Power Transfer Unit Input Shaft Seal RH . |
| Leaking gear lubricant from left hand side | Power transfer unit input shaft seal - LH and PTU to transmission compression seal | INSTALL new seals. REFER to: Power Transfer Unit Input Shaft Seal LH - 8-Speed Automatic Transmission - 8F35 . |
| 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 power transfer unit vent REPLACE the leaking seal. Refer to REMOVAL AND INSTALLATION |
| Automatic transmission fluid leaking into PTU or PTU gear lubricant leaking into transmission | Connecting sleeve to input shaft O-Ring | INSTALL new seals. REFER to: Power Transfer Unit Input Shaft Seal LH - 8-Speed Automatic Transmission - 8F35 . |
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.