Symptom Chart Four-Wheel Drive (4WD) System
Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. REFER to: Diagnostic Methods .
In most circumstances, the TCCM sets DTCs to help guide with diagnostics. Refer to DTC Chart: Transfer Case Control Module (TCCM) before using the symptom chart. The Symptom 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 |
|---|---|---|
| No communication with the TCCM | Scan tool DLC TCCM Wiring, terminals or connectors. |
REFER to: Communications Network . |
| The 4X4 mode indicators do not operate correctly | Wiring, terminals or connectors 4WD system fault MSS IPC HS-CAN TCCM |
GO to Pinpoint Test C |
| The vehicle does not shift between 2H (2WD) and 4H modes correctly | Wiring, terminals or connectors MSS Continuous Vacuum Hublock (CVH) system Transfer case TCCM |
GO to Pinpoint Test D |
| The vehicle does not shift between 4H and 4L modes correctly | Wiring, terminals or connectors Continuous Vacuum Hublock (CVH) Continuous Vacuum Hublock (CVH) solenoid Transfer case Vacuum leaks Front axle assembly TCCM MSS |
GO to Pinpoint Test E |
| The front axle does not engage/disengage correctly | Transfer case and related components Continuous Vacuum Hublock (CVH) and related components Wheel/tire assemblies |
GO to Pinpoint Test F |
| Four-Wheel Drive (4WD) does not engage at speed correctly | Wiring, terminals or connectors Transfer case dual-cone synchronizer Front axle assembly TCCM |
GO to Pinpoint Test G |
| The transfer case jumps out of gear | CVH MSS Transfer case |
GO to Pinpoint Test H |
| Vehicle pulsates or shudders in a straight line (straight line driveline wind up) | Unmatched tire sizes Unequal amounts of tire wear Unequal tire inflation pressures Unmatched front and rear axle ratios Front and rear axles |
GO to Pinpoint Test I |
| Clunking noise during 4WD engagement, especially at high speeds | Vehicle speed Torque to the front axle |
GO to Pinpoint Test F |
| The transfer case makes noise | Unequal tire inflation pressures Unmatched tire sizes Unequal amounts of tire wear Internal components Fluid level |
MAKE SURE that all tires and wheels are the same size and the inflation pressures are correct. CHECK tire tread wear to see if there is more than 0.15 mm (0.06 in) difference in tread wear between front and rear. INTERCHANGE one front wheel and one rear wheel. ROAD TEST again. OPERATE the vehicle in all transmission 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: Diagnosis By Symptom 6-Speed Automatic Transmission - 6R100 . Or REFER to: Diagnosis By Symptom 6-Speed Automatic Transmission - 6R140 . If there is noise in all gears, DISASSEMBLE the transfer case. REFER to: Transfer Case . CHECK the planetary gears, the bearings, the upper and lower drive sprockets and drive chain for damage. INSTALL new parts as necessary. FILL with the specified fluid. |
| Unable to duplicate customer concern | 4WD system and/or related components | CARRY OUT the Electronic Shift-On-The-Fly (ESOF) Functional Test. GO to Pinpoint Test J |