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-   -   Replaced 4wd vacuum harness, now 4wd won't disengage. (http://www.wranglerforum.com/f218/replaced-4wd-vacuum-harness-now-4wd-wont-disengage-189136.html)

TwoPointFiveLiter 09-24-2012 08:36 PM

Replaced 4wd vacuum harness, now 4wd won't disengage.
 
'89 2.5L, Standard. All Stock.

My vacuum lines from the old harness were all cracked, and I didn't realize it for awhile, so I was running it for probably a few thousand miles like this.
It wasn't a problem though, because it stayed in 2wd fine and I didn't need the 4wd.

Anyways, I replaced the vaccuum lines today, and when I started it up, the 4WD light came on. I shifted to 4WD hi and it was still on. Shifted to 4wd low and it was still on and worked fine.

I decided to take a trip to the store and test it out, with the shifter in the 2WD position, seeing if it was disengaged and the light was just on for no reason or not. Got up to 45 and it started to rumble, so it was definately engaged. Tried again in the 4WD position, same thing.

Help! I need to fix it before Friday!

Tyewilly 09-24-2012 08:51 PM

It sounds like you have the harness 90° off on the t-case switch.

TwoPointFiveLiter 09-24-2012 09:37 PM

so like...where the vacuum lines plug onto the t-case, I have it on there wrong?

There were alignment things on the cluster, but I didnt look too close, I'll have to check it in the A.M.

TwoPointFiveLiter 09-25-2012 03:18 PM

Checked it. Pulled it out and put it back in, same thing. There's 2 indents on the sides to ensure you are putting the cluster correctly into the t-case.

I did, however, pull the vac lines from the front end thinking it would disengage like it was before...nope.

4WD light was off, but it was still engaged.

TwoPointFiveLiter 09-25-2012 04:42 PM

I think I fixed it...

I read that someone with a cherokee and the NP231 t-case had the same problem. To fix it, he started the Jeep in neutral, then shifted all the way to 4wd low and back up to 2wd immediately.

Tried it and the light immediately went off. Gonna take a test run in a little bit.

kik 09-25-2012 04:50 PM

If that doesn't do it you might have to replace the switch on the transfer case. If you get the switch also get the O ring to go with it.

mbrinz76 02-21-2013 01:27 PM

  1. Raise and support the vehicle safely.
  2. 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.
  3. 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.
  4. Connect the vacuum pump to the rear port. Cap the port for the indicator lamp switch and apply 15 in. Hg (381mm Hg).
  5. 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.
  6. 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.
  7. 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!
  1. 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.
  2. Fig. 1: Command-TracŪ vacuum control system http://arrc.ebscohost.com/statics/p5...5/85357331.gif
  1. Fig. 2: Command-TracŪ vacuum axle shift motor
http://arrc.ebscohost.com/statics/p5...5/85357332.gif

mbrinz76 02-21-2013 01:36 PM

Fig. 1: Front axle shift motor and housing http://arrc.ebscohost.com/statics/p5...5/85357330.gif
  1. Raise and support the front end on jackstands.
  2. Place a drain pan under the shift motor.
  3. Disconnect the vacuum harness at the motor.
  4. Remove the attaching bolts and slowly lift off the motor and housing. Matchmark the shift fork and housing for installation reference.
  5. Rotate the motor and remove the shift fork and motor snaprings.
  6. Remove the motor from the housing and remove and discard the motor O-ring.
  7. When installing the motor, always use a new O-ring. Install the motor in the housing and slide the shift fork on the shaft.
  8. Position the housing and motor on the axle and add about 5 oz. of axle lubricant to the shift motor housing.
  9. Engage the fork in the shift collar and install the attaching bolts. Torque the bolts to 96 inch lbs. (11 Nm).


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