IWE System
IWE System Vacuum Diagram
| 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 |
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 IWE 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 IWE. An internal spring keeps the IWE clutch ring engaging the front hub and the front half shaft. The TCCM has a cold strategy which is used to warm up the front axle in cold temperatures to improve driveline synchronization. When ambient temperature is below 32 F (0 C), IWE engage after initial key cycle and a driven gear is selected. The hubs stay engaged regardless of 4x4 mode for approximately 2 miles (3km). Once distance traveled has been achieved the IWE disengage if vehicle is in 2WD (2H). Distance traveled resets only if the temperature is below calibrated threshold and another key cycle has occurred or customer shifted to park and back to drive within the same key cycle.