Will Not Engage In Two Wheel Drive

Fig. 1 Select drive vacuum control system. Eagle:

Fig. 2 Select drive vacuum routing in four wheel drive mode:

Fig. 3 Select drive vacuum routing in two wheel drive mode:

1. Raise vehicle on a suitable lift so that all four wheels are free to rotate, and start engine.
2. Disconnect mode selector vacuum harness at steel tube connection.
3. Using a suitable vacuum gauge, check for vacuum at steel tube that connects to red hose in mode selector vacuum harness. If vacuum is present stop engine, then proceed to step 5. If no vacuum is present, refer to next step.
4. Check intake manifold vacuum supply fitting, vacuum hose, and storage tank. Repair or replace damaged or leaking components. If vacuum leak still exists, check and replace vacuum hose from storage tank to steel tube, then recheck system. If there is no vacuum leak at this point, and two-wheel drive will still not engage, stop engine and proceed to next step.
5. Connect a suitable vacuum pump to steel tube that connects to green hose in harness. Apply 20 inches of vacuum and rotate rear propeller shaft to engage transfer case, then shift transmission into park (if automatic) or first gear (if manual). If transfer case does not engage proceed to step 8. If transfer case does engage, refer to next step.
6. Rotate right front wheel, front axle should be disengaged. If front axle shift motor operates properly and front axle is disengaged, check mode selector switch and vacuum harness, repair as necessary and recheck system. If front axle will not disengage, refer to next step.
7. Check vacuum tubes and lines, repair as necessary. If axle shift motor is still inoperative, check axle shift motor operation. Refer to "Axle Shift Motor Function Test." If axle shift motor is still inoperative, replace motor. If axle shift motor is operational and axle will not disengage, remove shift housing cover and axle shift motor. Inspect shift fork, collar and axle components, repair and recheck system.



8. Check transfer case shift motor, motor stem should be extended. If stem is extended then transfer case motor is operational. If stem is not extended then proceed to next step.
9. Check vacuum and tubes for leaks or damage, repair as necessary. If transfer case motor is still inoperative, refer to next step.
10. Check transfer case shift motor operation. Refer to "Transfer Case Shift Motor Function Test." If transfer case shift motor is still inoperative, replace motor and recheck system. If transfer case shift motor is operational and transfer case will not engage in two wheel drive, refer to next step.
11. Check axle shift linkage and repair as necessary. If transfer case will still not engage in two wheel drive, repair transfer case as necessary. If transfer case now engages in two wheel drive, proceed to next step.
12. Check axle for two wheel mode engagement. If front axle is in two wheel drive, recheck system. If front axle is not in two wheel drive, check axle shift motor, replace if necessary.