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Old 12-09-2013, 06:43 PM   #1
jeremyx28's Avatar
Join Date: Apr 2013
Location: Peckville, PA
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perm lock vs posi lock

My 4wd indicator lights not working. I had a new trans put in, it worked before the install but not after. From what I can tell all the vaccum hoses look good, I crawled under the jeep today and checked everything out. So I was thinking about going with a posi lock system. I'm not even sure if it will fix my problem with the light. I found a perm lock system for 1/2 the price of the posi lock. Being that I have a front lock right locker am I going to run into problems with the perm lock? Also, it feels like my 4wd is working despite the light not coming on, however I read on here that I'm not locked in....

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Old 12-09-2013, 08:19 PM   #2

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Location: North Las Vegas
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You shouldn't have problem with the locker until you select 4H or 4L with the transfer case.

The locker won't engage until it is told to, that is the way mine is working but I have a TJ shaft in the right front and did away with the CAD.

89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.

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Old 12-09-2013, 08:56 PM   #3
Join Date: Oct 2013
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Check the 4-way vacuum connection plug where it connects to the top of the tcase.

Its the 4-way connection you can see here in the middle area of the tcase between the 6 tranny mount studs & front output fixed yoke.

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Old 12-09-2013, 10:30 PM   #4
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Check the sensor for 4WD before anything. It is on the CAD housing. Either use a tester to check continuity with it open and closed, or close the circuit on the wire going to the sensor and see if the light turns on.

95 YJ, 2.5 AX15 conversion, 4.0 TB, SOA +1.5", 33" DC Crusher Tires, 8.8 Rear w/welded tubes + LSD, Spartan Locker HP30 Front w/solid axle swap, Rocky Road OTT kit, Safari Snorkel, Warn VR8000 Winch, Smittybuilt front Bumper, JKS Disconnects, AA SYE, Teraflex Shock Bar in Rear, 1/2" Boomerang Shackles, RE Add a Leafs, Homebrew Traction Bar, Monstalined in&out, LED Tail lights, 1700 Watt Stereo
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Old 12-09-2013, 11:09 PM   #5
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Location: Reno, Nevada
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If you feel like spending a bit of time you can do your own posi lock, here's a link to a write up I found on jeep forum when I had 4x4 problems
Home made POSI LOCK write up -
1989 Base YJ, 4.2l, Borla exhaust, offy intake, Motorcraft 2150 carb, CRT HEI ignition, ax15, np231 JB conversions SYE, D30 ARB & Ford 8.8 ARB 4.56, 35x12.5r15 Goodyear MTR's, bds 3.5" springs, 1" body lift, and 1/2" Boom Shackles.
Build Thread:
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Old 12-10-2013, 08:43 AM   #6
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Location: Plymouth, CT
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Start easy. Check the bulb in the dash. Then move to the switch. Unplug the wire at the CAD an short the two conductors with a small piece of wire.

Check those and post back. We can trouble shoot further.

If it feels like 4 wheel is working then it's probably one of those two things.

If your 4 wheel is out, then check the vacuum system, make sure you are getting vacuum on the switched side. If not, your vacuum switch may be bad. Then make sure the diaphragm isn't full of rust and mud and moves freely. If both of those are fine pull the CAD cover and make sure your shift fork isn't broken and that the collar slides easily over the splines of the outside axle shaft.

Good luck!

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