Axle Lockers

The rear differential will LOCK only when ALL  the following conditions are met:

• vehicle speed less than 5 KPH (3 MPH)
• transfer case in 4 LO position
• switch position for the corresponding axle is in the LOCK position
• ignition switch in the RUN or START position
• no locking differential or communication faults detected by the Final Drive Control Module (FDCM)

The front differential will LOCK only when ALL  the following conditions are met:

• front axle will not lock until the rear axle is locked
• vehicle speed less than 16KPH (10 MPH)
• left front to right front wheel speed difference less than 5 KPH (3 MPH)
• transfer case in 4 LO position
• switch position for the corresponding axle is in the LOCK position
• ignition switch in the RUN or START position
• no locking differential or communication faults detected by the FDCM

The differentials will UNLOCK when ANY  of the following conditions are met:

• transfer case in 4 HI, 2 WD, or Neutral
• front differential will UNLOCK when switch is in OPEN or RR, rear differential will UNLOCK when switch is in OPEN
• axle or communication faults are detected
• ignition switch is removed from the RUN or START position

Axle Lock Failsafes:

• Axles will UNLOCK with ignition off even if switch position is still in the LOCK position. The module will relock the axles on ignition on if the required conditions are met.
• Axles will not LOCK if there is no ignition switch, vehicle speed, or transfer case position signal. Axles will UNLOCK with the loss of any of these signals.
• Axles will not LOCK if the ignition switch is not in RUN or START
• Axles will UNLOCK with the loss of ignition switch, vehicle speed, transfer case position signal, axle lock switch signals, axle faults, or communication faults.