atlnq9 Posted January 27, 2009 Share Posted January 27, 2009 I got a few questions on the 4x4. So when I put it in four high are the hubs suppose to be locked all the time or only when there is slipping? The light says part time and it comes on and off when in four high. A bit confused because sometimes when it is four high the hubs don't seem locked, and the light is off. Half the time this happens driving would have been better if they were locked... This setup doesn't seem the same as my yj. Any insight, is this normal and something that is different about the "part time" compared to the wrangler, something I just have to get use to. Or are my hubs going bad, or vacuum, I think they lock by vacuum? Thanks, Andrew Link to comment Share on other sites More sharing options...
Eagle Posted January 27, 2009 Share Posted January 27, 2009 The MJ does not have locking hubs, the stub axles are always engaged. What it has is a central axle disconnect on the right side axle shaft, just like on the YJ. The disconnect is vacuum actuated, and if the light is blinking on and off my guuess is that you have a vacuum leak and it is disengaging itself at random times. There's a vacuum harness that plugs onto the vacuum fittings on the shift motor. That happens to be directly beneath the oil filter, and years of oil changes may have dripped enough oil on it to soften the boots to where they won't make a good seal. If that's the case, you have two choices: Buy a new vacuum harness for about $20; or manually engage the axle, shim it to stay that way, and forget it. Link to comment Share on other sites More sharing options...
maddzz1 Posted January 27, 2009 Share Posted January 27, 2009 :hijack: I also wondered about this because my light has never come on when I put it in 4hi. Until I read a thread last week I didnt even know there was a light. After reading that I decided to try and put my transfer case into neutral to see if it was even shifting and it would not shift past 4hi. So now I need to check the linkage when it warms up. If I lock the shift fork over how can I tell if it is actually shifting into 4WD when I put it in 4hi? Link to comment Share on other sites More sharing options...
702_MJ Posted January 27, 2009 Share Posted January 27, 2009 :agree: with eagle :hijack: I also wondered about this because my light has never come on when I put it in 4hi. Until I read a thread last week I didnt even know there was a light. After reading that I decided to try and put my transfer case into neutral to see if it was even shifting and it would not shift past 4hi. So now I need to check the linkage when it warms up. If I lock the shift fork over how can I tell if it is actually shifting into 4WD when I put it in 4hi? An easy way to see if its in 4wd, go out on the street and engage it and turn your wheels and drive a little bit. If you feel the tires bite and grab the pavement. you will know if it is it will behave completely different, i call it walking but it will feel like the truck is pulling. Believe me you will know. don't do it for long though, chance to break something. i didnt find out i had the light till i yanked it into 4wd furiously after breaking a rear end burning out. Link to comment Share on other sites More sharing options...
Pete M Posted January 27, 2009 Share Posted January 27, 2009 The t-case handle is all the evidence you'll need. If it is lubed and aligned, it'll just feel right when you shift into 4-hi (but never on dry pavement of course). In my opinion, the front CAD and that silly light should be done away with. Heck, my 88 doesn't have either since it was 2wd from the factory. Never had an issue with knowing what the t-case was doing. :D But if you simply must have that light, route the vacuum from the t-case straight to the little switch that activates the light. I think it's on the passenger side on the engine bay. :thumbsup: Link to comment Share on other sites More sharing options...
atlnq9 Posted January 27, 2009 Author Share Posted January 27, 2009 An easy way to see if its in 4wd, go out on the street and engage it and turn your wheels and drive a little bit. If you feel the tires bite and grab the pavement. you will know if it is it will behave completely different, i call it walking but it will feel like the truck is pulling. Believe me you will know. don't do it for long though, chance to break something. i didnt find out i had the light till i yanked it into 4wd furiously after breaking a rear end burning out. Yeah I tried that earlier on dry pavement real quick and sometimes I could definitely feel it and others it definitely wasn't there... That is when I got concerned. I didn't think the wrangler had command track? I could have sworn the axels looked different too, but then it has been probably two years since I have looked at it. Right now it is parked awaiting funds to get it going again. Edit: I don't really care about the light, at first I thought it ws a short, but now I am positive that tthe front axel isn't always engaged because I was all over the road in this ice sometimes and then others in perfect controll, if this ice wasn't here I would crawl under therre and see what t-case I got. 231 sounds familiar was that an option? Link to comment Share on other sites More sharing options...
maddzz1 Posted January 27, 2009 Share Posted January 27, 2009 After 86, the 231 is the only TC available on an MJ Link to comment Share on other sites More sharing options...
Pete M Posted January 27, 2009 Share Posted January 27, 2009 And I believe all Wranglers had the command-trac. Early models had the 207, later ones got the 231. Through 95 will have the dreaded CAD. Link to comment Share on other sites More sharing options...
702_MJ Posted January 27, 2009 Share Posted January 27, 2009 well i think the command trac came with the np242. Np231 i thought was the run of the mill transfercase. But its a part time t case. Could be a vacuum line leak like eagle said. I would look at that too as long as your under there. what is CAD? Link to comment Share on other sites More sharing options...
atlnq9 Posted January 27, 2009 Author Share Posted January 27, 2009 Well shows how much I remember about it. Is the Posi-Lok a worthwhile addition, granted $220 is a lot more than the vacuum hose, assuming that is my only problem, but it could be like the axle shift motor or the switch on the t-case right? thanks Link to comment Share on other sites More sharing options...
Pete M Posted January 27, 2009 Share Posted January 27, 2009 CAD stand for Central Axle Disconnect. :thumbsup: And select-trac is a Jeep term that esentially means there is an option in the t-case that permits all-surface-drive (meaning running on dry pavement won't hurt the t-case). The 242 has that, the 231 does not (and should not be used on dry pavement). I don't recommend the Posi-loc. All you need to do is shim the CAD to be engaged all the time and it'll never fail on you again. :thumbsup: Link to comment Share on other sites More sharing options...
atlnq9 Posted January 27, 2009 Author Share Posted January 27, 2009 Wouldn't shimming it be harder on the front axle for a daily driver? I am considering it now. Link to comment Share on other sites More sharing options...
Pete M Posted January 27, 2009 Share Posted January 27, 2009 Nope. It will behave just like any Jeep axle that didn't have the stupid CAD. Jeep did away with it in XJs in the early 90s and the YJ after the model change in 95. Our best guess is that it was done on the theory that preventing the front driveshaft from spinning in 2wd would reduce wear on the parts and increase mpgs. It does neither of those to any measurable degree. The one bad-ish thing that could happen is that you'll find out that one of your front driveshaft U-joints is worn out if you feel vibrations on the highway (since it's now spinning all the time). Link to comment Share on other sites More sharing options...
Eagle Posted January 27, 2009 Share Posted January 27, 2009 well i think the command trac came with the np242. Np231 i thought was the run of the mill transfercase. But its a part time t case. Could be a vacuum line leak like eagle said. I would look at that too as long as your under there. Command-Trac referred to the 207 t-case up through 1986, and to the 231 after that. The 242 (and from 84 thru 86 the 228/229) was called Selec-Trac. Command-Trac was the base 4WD, and Selec-Trac was the option with full-time 4WD available. Link to comment Share on other sites More sharing options...
702_MJ Posted January 27, 2009 Share Posted January 27, 2009 Oh ok i don't got one of those, i got a 92 axle. There i go with the terms again. Select trac command trac man all these terms ahhhhhhhhhhhh :headpop: Just kidding i never did any research into them i just assumed. But at least you got people like pete and eagle to correct me :thumbsup: Link to comment Share on other sites More sharing options...
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