Jeep Wrangler/YJ 1987-1995 Repair Guide

Command-Trac® Shift Motor and Housing

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REMOVAL & INSTALLATION



See Figure 1



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Fig. Fig. 1: Front axle shift motor and housing

  1. Raise and support the front end on jackstands.
  2.  
  3. Place a drain pan under the shift motor.
  4.  
  5. Disconnect the vacuum harness at the motor.
  6.  
  7. Remove the attaching bolts and slowly lift off the motor and housing. Matchmark the shift fork and housing for installation reference.
  8.  
  9. Rotate the motor and remove the shift fork and motor snaprings.
  10.  
  11. Remove the motor from the housing and remove and discard the motor O-ring.
  12.  
  13. When installing the motor, always use a new O-ring. Install the motor in the housing and slide the shift fork on the shaft.
  14.  
  15. Position the housing and motor on the axle and add about 5 oz. of axle lubricant to the shift motor housing.
  16.  
  17. Engage the fork in the shift collar and install the attaching bolts. Torque the bolts to 96 inch lbs. (11 Nm).
  18.  

FUNCTIONAL TEST



See Figures 2 and 3

  1. Raise and support the vehicle safely.
  2.  
  3. Disconnect the vacuum harness and connect a hand vacuum pump to the front port. Apply 15 in. Hg (381mm Hg) of vacuum to the front port and rotate the right front wheel to fully disengage axle shafts.
  4.  
  5. The shift motor should maintain the vacuum applied to the front port for a minimum of 30 seconds. If the motor does not maintain the vacuum, replace it. If the motor does maintain vacuum go to Step 4.
  6.  
  7. Connect the vacuum pump to the rear port. Cap the port for the indicator lamp switch and apply 15 in. Hg (381mm Hg).
  8.  
  9. The shift motor should maintain the vacuum applied to the rear port for a minimum of 30 seconds. If the motor does not maintain the vacuum, replace it. If the motor does maintain vacuum go to Step 6.
  10.  
  11. Remove the cap from the port for the indicator lamp switch and determine if vacuum is present. If present, the shift motor is functioning properly. If not, proceed to Step 7.
  12.  
  13. Apply 15 in. Hg (381mm Hg) of vacuum to the shift motor rear port. Rotate the right front wheel to engage the axle shafts. The axles must be completely engaged!
  14.  
  15. Determine if vacuum is present at the port for the indicator lamp switch. If present, the shift motor is functioning properly. If not, replace the shift motor.
  16.  



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Fig. Fig. 2: Command-Trac® vacuum control system



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Fig. Fig. 3: Command-Trac® vacuum axle shift motor

 
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