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Unread 12-09-2009, 11:52 AM   #1
snowcrawlr619
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1995 YJ Wrangler 
 
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vacuum system hoses all hooked up but system doesnt work

as in the title, i got under there and made sure all the hoses go where they need to. i researched all the diagrams to be sure. but my front axle still refuses to engage when i shift into 4wd. i know its an old problem that everyone is tired of hearing but my dad and i are stumped. so could it be electrical? or mechanical? i appreciate any and all help

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Unread 12-09-2009, 12:11 PM   #2
MJMPC
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Have you checked for vac at the disco ? If you have vac then it might be the vac motor is bad .
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Unread 12-09-2009, 10:30 PM   #3
snowcrawlr619
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yea i checked that. i think it might be the motor too. im praying that its not the fork or anything id have to tear into the axle for. so yea il buy a new motor and see what that does. thanks!
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Unread 12-10-2009, 06:36 AM   #4
muddy93
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swapping the shift fork is not that big of a deal, it's only 4 bolts, and a couple little clips. And, in order to swap the shift motor/actuator, you're going to have to pull the CAD housing anyway, which will expose the shift fork, colar, and axle splines.

anyway, are you positive that the axle is not engaging, and that it's not just a burnt out bulb?

first, make sure that the T-case is engaging, with the engine off, shift the T-case into 4wd, and crawl under the jeep and see if you can turn the front drive shaft. if you can, then you have a T-case or T-case linkage problem. if you can NOT turn the drive shaft, then the T-case is ok, and you can move on to the front axle.

jack the passanger side front tire off the ground (block wheels, and support with a jack stand),
with the engine running(transmission in park or neutral) and the T-case in 2wd, make sure that the passanger side front tire can spin freely. Then put the T-case into 4wd, and try to spin the tire again. If it still spins, then you have an axle disconnect problem.

Sense you already checked the hoses, the next thing would be the vacuum switch on the T-case. You can test it by disconnecting the vac lines from the front axle, see which line has vacuum when in 2wd. Then shift the T-case into 4wd. The vacuum should switch lines. If it dose, then the vac switch is ok.

If the vacuum switch is ok, the only thing left is the vacuum actuator(motor) on the front axle. like I already said, it's only 4 bolts to take it off, and then you can inspect the fork, colar, and axle splines to make sure they are all ok. also, wile you have the actuator off, if you have a hand vac pump, hook it up to the actuator, and make sure that it moves, and that there are no leaks in the diaphram.
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Unread 12-10-2009, 06:46 AM   #5
mrmud4x4
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Quote:
Originally Posted by StreetJeep5 View Post
yea i checked that. i think it might be the motor too. im praying that its not the fork or anything id have to tear into the axle for. so yea il buy a new motor and see what that does. thanks!
It's real easy to pull that cover off and look at the area where the fork is, just make sure when you put it back, the fork is on the axle slide.....you'll see, real easy! If the fork is broke, that should be simple to fix also.


Go Posi-lok....that's what I did....research it here or google it.
I pull my posi-lok cable when rolling real slow.....and can feel it "pop" in and the cable locks in position. Works great!
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Unread 12-10-2009, 04:53 PM   #6
snowcrawlr619
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thanks for the help guys. muddy93 im gunna try that this weekend and that list is a huge help. even if i do figure this out i do plan to posi-lok it just incase. happy holidays guys i appreciate it all!
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Unread 12-10-2009, 04:55 PM   #7
snowcrawlr619
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oh and the funny thing is i actually replaced all of my guage bulbs with blue LEDs so that wont be a problem for awhile... hopefully
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Unread 12-23-2009, 10:39 PM   #8
Bfraley
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I have another question for you guys. I cut my vacuum lines replacing the floor board on the passenger side. I spliced them all back together and my 4WD works. When in 4WD High the light (light on top) works, when in 4WD Low the same light stays on (light on top), the 4WD Low light does not turn on, the 4WD High light (light on top) stays on. Any Ideas?
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Unread 12-28-2009, 07:52 AM   #9
muddy93
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There is NO specific "4lo" light. There is only a 4wd light.
the switch for the light is on the front axle, and is activated when the shift fork moves over to connect the two pieces of the passanger side axle shaft.
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