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Old 03-30-2012, 09:23 PM   #1
JenkinsJeep95's Avatar
Join Date: Dec 2010
Posts: 47
Unhappy Need Help! Loud pop and a 4WD light

OK once again I need the expertise of you wonderful people on the YJ forums. Unfortunately my Jeep has been off the road for the past couple years. I was just driving it home from the mechanics where much work was done to get it road worthy again. I was ecstatic my YJ was still among the living, but upon turning onto my street I heard a loud pop/grind noise come from underneath/behind me and then my 4WD light came on. I was at my house so I pulled in and got out to check it out. I couldn't see anything wrong, so I jumped back in, ran through 4WDHi, N, 4WDLo, and 2WD before leaving it in 2WD. This did not do anything for the problem however. The light remains on and the noise occurs every time I turn the wheel sharply. Your help is greatly needed as I am afraid dishing out any more cash for a mechanic is out of the question. Thanks!

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Old 03-31-2012, 08:09 AM   #2
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Posts: 341
The 4wd light is turned on by the Vacuum motor in the front axle. Sounds like something might have went wrong there.

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Old 04-01-2012, 05:32 PM   #3
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Smile Thanks

Yeah, It took some research to figure out but as it happens I was having 2 separate problems that happened simultaneously. The vacuum motor went out and I fixed that, but also my spider gears in my rear diff. were chewed up pretty good thanks to whoever worked on it last not shimming it properly and it wore down the carrier. But it is all taken care of now. Thanks for the input.
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Old 04-02-2012, 05:23 PM   #4
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Location: Alabama
Posts: 142
Where us the vacuum motor is that the cad. If the cad goes bad will 4WD drive light stay on all the time?
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Old 04-04-2012, 08:47 AM   #5
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It is my understanding that is the motor or switch goes bad then the vacuum could lock the hub even if your not in 4wd or it could just cause the light to stay on since the light is activated by the vacuum as well. If your having that problem there is a sticky at the top of the threads that can tell you how to diagnose and repair.
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4wd , 4wd light , loud pop noise

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