4WD Not working

J

jocar

New member
1046038

Hey Guy's and Gals!



I have a 91 Jeep Cherokee with the 4.0 HO engine in it. About 3-4 months ago, I locked it into 4wd to get the axles and drivetrain working a little and noticed that my indicator light on the dashboard didn't come on. At the time, not being off road or anything, I didn't think much about it. However, I recently attempted to use my 4wd and found out that it no longer works. It seems like the transfer case is doing it's part but the front axle appears not to be doing it's job for some reason. Has anyone seen this before? or know something that I can check to see? Any ideas or comments will be welcome! Thanks!



Joe Carr[addsig]
 

1046042

On the rear right side of the front axle there is a little housing, with some vacumn lines and an electrical connector. I believe the electrical connector is for the light, and the vacumn lines move a fork inside the axle housing that moves a sleeve that engauges and disengauges the right front axle. Mine sticks on occasion and muiltiple shifts, a little reverse and drive, someitmes a short drive stop, drive stop while shifting from 2 high to 4 high managed to loosen things up. Had a vacumn leak awhile back that wouldn´t allow enough vacumn to make the shift (also messed up the heater controls). Also had a burr on the axle splins, that sometimes wouldn´t let it shift all the way in (would make a ratcheting sound) filed that smooth. Most times it like anything else, if it´s not used often enough it gets sticky. It seems the more I used it the better it worked. Had the shift motor (that housing on the axle) apart a few times no big deal. A little cleaning and silsicon makes a new gasket. Jacking up the right side of the front axle, keeps most of the oil from running out. A person could probably run a test with the shift motor out, have somebody (with the wheels blocked good) shift the transfer from 2 to 4 and watch and see what the shift fork does (watch your fingers). I´ve moved the sleeve right and left with a little prying from a screw driver (just make sure it lines up the same for reassembly, that the fork goes in the slot). Hope I´ve been more help, than confusion
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[addsig]
 
1046043

The front axle disonnect is not working properly. It is vacuum controlled, so start by checking the following:

1)Jeep running, in neutral or park with e-brake on

2)Remove the two vacuum lines from the front axle disconnect (on pass. side)

3)Have somebody you trust shift Jeep into 4wd and back to 2wd

4)Feel for strong vacuum in one line in 2wd and other line in 4wd



If that checks out okay, the problem is in the front axle. Remove the shift motor (held to axle with 4 bolts) and work the shift fork back and forth by hand. Clean with WD40 and spray into both vacuum ports while moving the shift fork. Reassemble and hook up the vacuum lines. It SHOULD work now.



If the vacuum check is not okay, either the vacuum switch in the transfer case is bad or there is no vacuum to the transfer case from the intake manifold. The vacuum switch in the transfer case is easy to replace, it threads into the transfer case on the pass. side.



Let me know what you find, I'll help as best I can.



One more thing, it's pretty common for the vacuum lines to be cut near the battery, often due to battery acid. Also check for nicked/cut vacuum lines if the vacuum is weak at the front axle.[addsig]
 

1046083

I need to save that, it's a common problem and so much to write down.[addsig]
 
1046114

Thanks to all that have replied with the excellent advice! Unfortunately, I won't be able to check on any of this for a couple of days due to some medical problems, but most definately will. I just wanted to say ahead of time, thanks to all for the assistance on this! I really appreciate it![addsig]
 
1046224

1991 XJ cherokee does not have a front axle disconnect. The front is engaged at all times. They stopped using the disconects around 1987or 1988. My 86 XJ had one, my 89 xj and my 94 xj do not. This sounds like a t-case problem. Probably the light switch.[addsig]
 

1046233

I havn´t looked under every year of XJ, but I also assumed (assumptions will sometimes get ya in trouble) the difference in front axles was the difference in the command track and the select track transfers. Often wondered, when Jeep did major model revisions, in the XJ 86 or 87, 91 or 93, 95 or 96. I sometimes get my layouts confused, easy to do with Jeep. They sometimes have two different layouts running at the same time in the same body, never did figure out when the V-6 stopped and the I, 6, 4 Ltr. began at which factory, Canadian or U.S. That´s what makes Jeeps so much fun, you don´t often know what you have, until you get in there with a flashlight and start reading labels and looking at things.
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[addsig]
 
1046235

I really, really really hate to say it but "life ( in this case Jeeps)is like a box of chocolates". My 86 was a part-time only case, my 89 is a full-time/part-time case and my 94 is a part-time case. The only one of the lot with a disconnect was the 86. And i think i remember my buddy at the parts dept of the dealer telling me 86 was the last one. That may only be in the US.[addsig]
 
1046258

My 87 XJ (command trac) had a disconnect, my buddies 93 (selec trac) didin´t, my 91 YJ (command trac) did, my 96 XJ (selec trac) doesn´t. I guess other than all data, the only way to know for sure is to get the old knees dirty. Most all of the vacumn diagrams and electrical diagrams I look at, say typical somewhere in there, which leads me to believe there are some non-typicals out there also. Saw a buddies XJ with a chrysler rear axle in there. Have to plead ignorance, until I look for myself.
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Your probably right as I havn´t been under a 91 XJ that I remember.[addsig]
 

1046369

The XJ used the front axle disconnect up until '91 with the Command Trac 4wd. What I described above will work for the '91.[addsig]
 
1046419

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE>Bounty hunter



Command track is part time ?? right??</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>



Yes. Selec-Trac has the extra full-time option on the transfer.[addsig]
 

1046530

so they did use the disconnect on the command track till 91 then? Kool, I guess you do learn something new everyday!!
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[addsig]
 
1046935

Update - I got under the jeep finally today!. The place on the front axle where the vacuum lines connect (that little round thing), the lines were barely hanging on there. When I moved them around a bit, you could hear air leaking. Are the vacuum lines supposed to be that loose? Also, that little round thing moves about a quarter of an inch back and forth, is that normal? forgive me for being a newbie at this! My old 4x4 was a Scout with manual hubs, a lot simpler to figure out. Anyways, it appears to me that there might be some sort of a vacuum leak on this thing, causing the front axle not to engage like it should. If that's the case, how do I fix it! I mean everything's there like it should be, it's just that the connector for the vacuum lines seemed like it was just slid on with no snuggness or anything. Thanks for any assistance you'all! I really appreciate it! (forgive my spelling!)



Joe

[addsig]
 
1046938

Update number 2 - I Took out the vacuum thing, sprayed it down with wd 40 and degreaser, worked it back and forth and put it back together. After just a few seconds of putting it into 4 hi, the light came on, I drove it around and parked in a big mudhole, locked it in and out it went! IT Works! I want to thank all those who came to my aid on this. When I had my scout, I bought it out of a pasture and did all the work myself to get it back running. After that I got lazy, had several 4WD's and took it to the shop if something went wrong. I have learned a lot about my Cherokee looking around this site! Thanks again for all the help and you all be carefull out there! I know I will! and I will learn more about my Jeep.



Thanks!



Joe

[addsig]
 
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