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Discussion Starter · #1 ·
This one is for all you YJ guys. I have an 89 and the 4x4 100% does not work. Here is the question for you guys. On the 4x4 harness there is a one way valve, after this valve is where I need the help. I have pretty much nothing after it. Where is this supposed to go to? Also does anyone know which way the valve is supposed to go? The valve was missing on mine so I bought one at the local dealer for $4.00 just need to figure out what's after.

Thanks in advance,
Dave

98 XJ Cherokee Sport
89 YJ Wrangler Laredo
 

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do a search for this thread: need help with a np231 - it won't engage the front drive

there is a pretty good discussion on what could go wrong.

79/CJ-7/AMC360/TH400/Q-TRAC/d30/d44/33's/RS9000s/Herculiner
 
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Discussion Starter · #3 ·
I couldn't actually find any threads that matched your search string I did find some threads but sadly none that help out. Any other ideas?

Dave

98 XJ Cherokee Sport
89 YJ Wrangler Laredo
 
G

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Discussion Starter · #4 ·
Take it to the Jeep dealership and get them to tell you what's wrong. After you know what's wrong with it, take it home and fix or replace the parts yourself.

 

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Dave,
I don't quite follow you. Are you saying that all the vacuum tubing to the front axle is missing? Where is this "4x4 harness" and one way valve located?
/wwwthreads_images/icons/tongue.gif
 

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try this instead: yj's wasn't engaging the front driveshaft

be sure to search in short wheelbase, entire phrase, all posts. this came up with it.

79/CJ-7/AMC360/TH400/Q-TRAC/d30/d44/33's/RS9000s/Herculiner
 
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Discussion Starter · #8 ·
The harness is attached to the front axle as well as the transfer case. But there is a blue vaccume tube that is part of the harness that has a one way release valve on it this is where my question started in that I have the valve but there is a nipple on both ends of the valve leading me to believe that something else goes on the end. The location of the valve is just under the battery tray, it should be sticking out the side of the harness.

Dave

98 XJ Cherokee Sport
89 YJ Wrangler Laredo
 

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dioxide,
I am having the same problem with the 4wd not working on my 88. Do you have the vacuum harness in tact from the transfer case to the front axle? There should be three hoses that go the the motor on the axle, two that run up to the engine compartment, and four that come off of the transfer case hooked to a rubber plug that hooks to the top of the tcase. This is called a vacuum harness if you can't find the name for it. The dealership I purchased mine at had no clue what it was; the shop foreman had to order it for me. Costs about $30 dollars. After you hook it all up and you still don't have vacuum, check all of your vacuum connections for the engine(emissions). The 4wd runs off of the same lines.(pretty sure). Look in your Haynes manual for the Vacuum diagram for the correct way to hook everything up. If that was your problem, I hope this helps. I have to take mine to my mech to rehook all of my vacuum correctly since I still don't know what everything on my 258 is called or does.
Good luck.
B

 

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Dioxide,
I think that blue tube with the check valve on the end of it just hangs there, serving as a vent. My 86 Cherokee has the same front axle disconnect system as your YJ, just the physical locations of all the parts are different. Your 98 XJ doesn't have the disconnect, so you can't look at it for help. There are 3 tubes on the axle shift motor, one being 4wd, another being 2wd and the third is a connection to a "vacuum to electric" switch for the dashboard 4wd light. Start the engine, leave the transfer case in 2wd, crawl under the Jeep and see if there is vacuum in one of the tubes. Then shift the transfer case into 4wd and check to see if one of the other tubes now has vacuum. If you have vacuum at the shift motor in both 2wd and 4wd, then either your shift motor is bad or the axle collar is stuck. Remove the shift motor by loosening the 4 bolts. Check the collar to see if it is loose; if it is stuck, free it and grease the splines good with some axle grease. Check the shift motor to see if it moves back and forth when vacuum is applied to each port. Good luck!! /wwwthreads_images/icons/smile.gif
 
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