IWE System
IWE System Vacuum Diagram 2.7L GTDI
| Item | Description |
|---|---|
| 1 | Intake manifold |
| 2 | Brake booster |
| 3 | Vacuum pump |
| 4 | IWE vacuum reservoir |
| 5 | IWE solenoid |
| 6 | IWE vacuum actuator LH |
| 7 | IWE vacuum actuator RH |
IWE System Vacuum Diagram 3.3L / 3.5L GTDI
| Item | Description |
|---|---|
| 1 | Air cleaner outlet pipe |
| 2 | Brake booster |
| 3 | Intake manifold |
| 4 | IWE vacuum reservoir |
| 5 | IWE solenoid |
| 6 | IWE vacuum actuator LH |
| 7 | IWE vacuum actuator RH |
| 8 | Vacuum solenoid valve |
| 9 | Filter |
| 10 | Venturi |
| 11 | Aspirator assembly |
IWE System Vacuum Diagram 5.0L
| Item | Description |
|---|---|
| 1 | Air cleaner outlet pipe |
| 2 | Brake booster |
| 3 | Intake manifold |
| 4 | IWE vacuum reservoir |
| 5 | IWE solenoid |
| 6 | IWE vacuum actuator LH |
| 7 | IWE vacuum actuator RH |
IWE System Vacuum Diagram 3.0L
| Item | Description |
|---|---|
| 1 | Brake booster |
| 2 | Vacuum pump |
| 3 | IWE vacuum reservoir |
| 4 | IWE solenoid |
| 5 | IWE vacuum actuator LH |
| 6 | IWE vacuum actuator RH |
The IWE system consists of the following:
| 1 | IWEs (spring-loaded vacuum hubs) |
|---|---|
| 2 | Vacuum hoses |
| 3 | IWE solenoid |
| 4 | Vacuum reservoir |
The IWE system uses a vacuum solenoid and vacuum actuated hubs to engage or disengage the front wheel hubs from the front half shafts.
When the 4WD system is in 2WD (2H) mode, the TCCM supplies a ground path to the IWE solenoid to apply engine vacuum to the IWEs thus disengaging the front hubs from the front half shafts. To maintain vacuum during all modes of engine operation, a one way vacuum check valve and a vacuum reservoir are positioned between the vacuum source and the IWE solenoid.
When operating in any 4WD mode, the TCCM does not supply the ground path to the IWE solenoid. Vacuum is not applied to the IWEs. An internal spring keeps the IWE clutch ring engaging the front hub and the front half shaft.
The TCCM has two startup strategies that affect IWE operation after initial key cycle:
- When ambient temperature is below 32 F (0 C), IWEs engage after initial key cycle and a driven gear is selected. The hubs stay engaged regardless of a 4x4 mode change for approximately 2 miles (3km). Once the set distance has been achieved, IWEs disengage (if the vehicle is in 2WD (2H)). Distance traveled resets only if the temperature is below calibrated threshold and another key cycle occurs or if customer shifts to Park (P) and back to a driven gear within the same key cycle. The TCCM uses this strategy to warm up the front axle in cold temperatures to improve driveline synchronization.
- When ambient temperature is above 32 F (0 C), IWEs engage after the initial key cycle and a driven gear is selected. The hubs stay engaged regardless of a 4x4 mode change for approximately 0.5 miles (0.8km). Engagement only occurs once per key cycle and is not reset when shifting between Park (P) and Drive (D). The TCCM uses this strategy to delay vacuum use until vacuum-intensive engine startup has completed and sufficient vacuum is available to fully disengage IWEs.
Some engines are equipped with a brake booster vacuum pump that supplies vacuum to the IWE vacuum reservoir.