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Savvy/Currie Aluminum Control ArmsROCK BOTTOM prices on LIFT KITS at Rockridge4wd!! WANT TO December Specials at Jeephut.com

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Unread 08-19-2011, 12:19 PM   #1
mattdinko
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1992 YJ Wrangler 
 
Join Date: Aug 2011
Location: canton, Ohio
Posts: 2
yj 4x4 questions

im brand new to the world of 4x4s and just got myself a lifted yj. i though the front differential was locked in the stock dana 30 but i recently pulled the 4x4 vacuum lines and the indicator wire apart when i snagged a branch. i put them back together but since then only the driver side wheel spins in 4x4, does this mean there might be a problem with the vacuum system? the way i understood it was engaging 4x4 only really gave power to the driver side front and that the vacuum system engaged a 2 piece drive shaft to the passenger side? also the 4wd light is not coming on at all. any explanations or suggestions are greatly appreciated!

also how do you tell what the gearing is? the previous owner was as clueless as i am but it must be re geared since its running 35s and tops out at under 60mph lol



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Unread 08-19-2011, 12:31 PM   #2
bogleparsons
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2013 JK Wrangler 
 
Join Date: May 2011
Location: fayetteville, NC
Posts: 1,905
the problem with the 4x4 light and your right front passenger tire not spinning are both connected to your vaccum switch that connects the front axles.

to know what gears you have (assuming they are stock) its on a tag under one of the bolts on the rear end.

If you suspect the gearing has been changed you can jack the Jeep and spin the tire while watching the drive shaft. That also will tell you what ratio you have.

I just read your profile you have an 8.8 rear end so as to what stock gearing is i don't know
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Unread 08-19-2011, 01:13 PM   #3
dancytron
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1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: st. louis
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He has a 1992. His diagram is this. . .
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Unread 08-19-2011, 01:16 PM   #4
muddy93
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1987 FSJ Wagoneer 
 
Join Date: Aug 2007
Location: Templeton, Indiana
Posts: 1,908
In stock from, YJ front axles have open dif's. The CAD (Central Axle Disconnect) is just there to disconnect the passenger side axle shaft so that your front drive shaft doesn't spin all the time when in 2wd. It basically takes the place of manual hubs (like are found on most older 4x4's).

Also, due to how an open dif works, spinning only one tire (front or rear) is verry common.

For the light, check all the vac lines, and the wires for the light, and also check the bulb.
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Unread 08-19-2011, 01:34 PM   #5
mattdinko
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1992 YJ Wrangler 
 
Join Date: Aug 2011
Location: canton, Ohio
Posts: 2
thanks for the info ill look into replacing the switch and see if that works
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Unread 08-19-2011, 02:56 PM   #6
hrt4me
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1991 YJ Wrangler 
 
Join Date: Jun 2011
Location: Dallas, TX
Posts: 327
Quote:
Originally Posted by muddy93 View Post
In stock from, YJ front axles have open diff's. The CAD (Central Axle Disconnect) is just there to disconnect the passenger side axle shaft so that your front drive shaft doesn't spin all the time when in 2wd. It basically takes the place of manual hubs (like are found on most older 4x4's).

Also, due to how an open dif works, spinning only one tire (front or rear) is very common.

For the light, check all the vac lines, and the wires for the light, and also check the bulb.
thanks, I need to do these same checks for my own '91 YJ...
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Unread 08-19-2011, 02:58 PM   #7
dancytron
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1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: st. louis
Posts: 1,372
I'd replace the lines too. You can use regular black rubber from the autoparts store. If they are original and aren't bad now, they will be soon.
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axle , differential , vacuum , vacuum system , YJ

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