jeepcoma Posted December 31, 2008 Share Posted December 31, 2008 Took my MJ out to run some errands today, it was snowing and I thought it'd be a piece of cake. Yesterday I took apart the mini-console and bolted the transfer case lever back to the body (it was held it by only one bolt, and flopping around); once I did that I was able to shift it into all positions, although it was a bit sticky. I figured it was just from lack of use and crud buildup, the previous owner had been using the 4wd last year and said it was working, and I've been spraying everything with pb blaster daily to loosen things up. Being all excited for the snow I went out and shifted to 4H, and was greeted by a glowing light indicating part time 4wd. It doesn't seem to fully engage though, I could hear clicking noises coming from what sounded like the transfer case; it sounded like rocks being ground up, or if you've ever had the displeasure of hearing what an automatic transmission sounds like when forced into Park while in motion, that was it. I'm guessing that it's just the linkage out of adjustment, and that despite being able to move the lever from 2H all the way to 4L it's not really doing it. I rowed through the settings a few more times, and when it was in 4L it was actually in neutral, and now I put it in 2L and the part time light is still on. I read the easiest way to adjust is to loosen the linkage, manually place the transfer case to neutral and then put the lever in neutral, and then tighten the linkage again. Does the transfer case shifter have obvious detents in it that you can feel when shifting manually, like an automatic transmission that you can feel click into each setting? Best case scenario is that it's just the linkage not being properly operated by the hand lever. What would the worst case scenario be, or other common failures for an AX-15/NP231 combo? Does anyone have any pictures of this area? I'll go out and crawl under the truck in the snow to fix it but it'd be preferable to know exactly what I'm doing before lying in a foot of snow. Link to comment Share on other sites More sharing options...
jeepcoma Posted December 31, 2008 Author Share Posted December 31, 2008 I've also read about manually locking the vacuum actuated front axle disconnect. I might check into that more but the fact that when the lever is in 4L it's actually in neutral and now when in 2H it's actually 4H still leads me to think it's just the linkage. Link to comment Share on other sites More sharing options...
Pete M Posted December 31, 2008 Share Posted December 31, 2008 This may help out. But never underestimate the CAD's power to ruin the day. :D Link to comment Share on other sites More sharing options...
jeepcoma Posted December 31, 2008 Author Share Posted December 31, 2008 Thanks for the pic, I had seen that before but also found other recommendations about putting it in Neutral instead of 4L. Actually after reading further, I found a post that states 91+ went to solid axle, so I might not even have vacuum CAD? If that's true, from what I understand, the transfer case lever manually shifts into 4wd and there is no vacuum operating anything at all. If that's true, what could be the source of the grinding/ratcheting noise and no front drive? Also, is the part time light then operated by a switch, or something else? Link to comment Share on other sites More sharing options...
jeepcoma Posted December 31, 2008 Author Share Posted December 31, 2008 Found these great CAD pics others might find useful: viewtopic.php?p=21636#p21636 Link to comment Share on other sites More sharing options...
Pete M Posted December 31, 2008 Share Posted December 31, 2008 Thanks for the pic, I had seen that before but also found other recommendations about putting it in Neutral instead of 4L. Actually after reading further, I found a post that states 91+ went to solid axle, so I might not even have vacuum CAD? If that's true, from what I understand, the transfer case lever manually shifts into 4wd and there is no vacuum operating anything at all. If that's true, what could be the source of the grinding/ratcheting noise and no front drive? Also, is the part time light then operated by a switch, or something else? 91 is when they started phasing them out in XJs. They were completely gone by 93. All 4wd MJs should have the CAD except for the rare awd 86 MJs. The part time light is turned on by a vacuum switch. If I remember right, it's on the passenger side wheel well in the engine bay. The grinding noise could definitely be a CAD that's trying to engage, but can't for some reason. Link to comment Share on other sites More sharing options...
jeepcoma Posted December 31, 2008 Author Share Posted December 31, 2008 91 is when they started phasing them out in XJs. They were completely gone by 93. All 4wd MJs should have the CAD except for the rare awd 86 MJs. Ah, thanks for the clarification. Will dig a hole through the snow and check it out tomorrow, starting with vacuum lines and leaks. The noise was definitely more pronounced when turning, and also if I intentionally gunned the engine while driving on the snow to break the tires loose it would do it. Aside from the linkage being very difficult to move and apparently not moving the t-case lever the full range, the noise and problem I'm experiencing seems very similar to the problem covered in this thread. Once he locked the CAD it went away. Link to comment Share on other sites More sharing options...
jeepcoma Posted January 1, 2009 Author Share Posted January 1, 2009 Today I dug out the snow and got underneath and started poking around. I believe I have two separate problems. 1st is the CAD. It's all covered in crud and I haven't taken it off yet, but I did run the engine and could hear a vacuum leak when I moved the vacuum lines around. I couldn't really localize the noise, it didn't seem like it was coming from the attachment section but rather so I pulled the hoses out of the looms up until the point where it breaks away. I wasn't able to find anything obvious, but it seems like the best solution here is to disable the system and force it on full time. I suppose I could replace all the lines, but that's probably more trouble than it's worth for a system of dubious merit. One question though, where in the engine bay does the vacuum originate from (my hood is frozen shut at the moment, until it thaws out a bit)? While I was playing with the vacuum lines, I also noticed this hose dangling. It's not the source of the vacuum leak, but I'm not sure what it's supposed to be for. Any ideas? Okay so that's one problem, the grinding noise I'm getting when the front wheels are trying to pull and the CAD isn't fully engaged. Secondly is the linkage. I sat under the truck and had my wife push and pull the lever while I watched to see what was going on. It's definitely not right, but I'm not sure what it's supposed to look like. When pulling the lever back to 4L it takes a lot of force, and I could see the section of the floor the linkage is bolted to deforming from the strain. Also, it looks like the linkage is just twisting to the side instead of moving backwards. Here are two pics I got of the mechanism operating. You can see how it just sort of folds off to the side. And finally, here's a picture what that nut exposed. Is that the trunnion lock bolt I'm supposed to loosen for the adjustment? I've got the whole thing soaking in WD-40 again, I'll go out and see if anything has loosened up. I'm wondering if I should just replace the entire linkage mechanism, I'm wondering if things have been bent out of spec from being operated like this for so long. How much effort is it supposed to take to operate this thing? Link to comment Share on other sites More sharing options...
mvusse Posted January 1, 2009 Share Posted January 1, 2009 WD40 is meant to displace water and is a piss poor lubricant. If you ever try PB blaster, you will never figure out how you did without it. Link to comment Share on other sites More sharing options...
Pete M Posted January 1, 2009 Share Posted January 1, 2009 :agree: I would keep spraying with PB (or other rust penetrant) and working the linkage. Is your floor mushy from rust? Don't forget to spray in the cab to get the pivot point for the handle. I know there was an aftermarket company that made a shifting package that bolted purely to the transmission. The name escapes me though. :hmm: Link to comment Share on other sites More sharing options...
jeepcoma Posted January 1, 2009 Author Share Posted January 1, 2009 mvusse you're right about PB blaster. I've actually been using both, the reason for the WD-40 is that I've got a full can that's easy to squirt 2 feet or so with good aim onto the hard to reach parts. My can of PB is almost out so I have to be able to reach everything in order to spray it with a dribble. But it's been blasted with the PB a good 3 times or so over the past few days. I have the floor console apart so I'm also spraying down from the top and up from underneath. The floor isn't mushy from rust, but for some reason I can't figure out, one of the previous owners removed some of the hold-down bolts that attach the gate to the floor. So it was held down by just one bolt (or two, I can't see if there are four total but probably are), the one (or ones) on the driver's side. When you go to move the lever, you can see the whole thing just flexing. I don't know how long it's been like that, but I'm sure it hasn't been good for the floor integrity or linkages, which is probably why they're bent out of shape and not working right. Link to comment Share on other sites More sharing options...
jeepcoma Posted January 1, 2009 Author Share Posted January 1, 2009 Yay for some progress. I modified the CAD to be engaged full time. When I took it apart everything seemed to be working nicely though, it was clean and all the pieces moved smoothly. I didn't have any trouble sliding the collar piece up the shaft, and I didn't even have to hunt for the c-clip when it went flying on the ground. Here I am contemplating the workings of the CAD while enjoying an ice cold beverage. Afterwards I played around with the 4wd linkage some more. I think it's fubar. I removed the locknut, which should allow the rod to slide freely forward and backward, but instead it's rusted in place and no amount of persuasion with a hammer got it to budge. I ditched trying to adjust it and instead just need to be able to switch into 4H and 2H so I can drive it on pavement tomorrow for state inspection (yay). With the lever forced all the way forward into 2H I was able to knock the lever at the t-case side another good 1/2 inch or so - the reason why I couldn't disengage 4H once I got it in yesterday. I realized that was the reason for the bolts missing from the cabin that hold the lever in place, it was a mickey mouse job to get the broken linkage to work. Once I removed the holddown bolts I installed yesterday, I was able to shift into and out of 2H and 4H, although it's only a temporary fix since really all I did was put it back the way it was before. I did still get some noises from the t-case though with the truck stationary, I think it was just because I can't really tell now when it's fully engaged or not since the Part-Time light doesn't come on anymore. That shifting package that bolts to the tranny sounds like a solution I'll have to start looking for. I'm a little confused about what the CAD bypass actually does now though, because when I was in 4H mode I was able to spin a single front and a single rear wheel in the snow. I thought that when you engage 4H the front axle will act like a solid and the front wheel rotate at the same rate 100% of the time. Maybe I'm just not sure how the front axle works between 2 and 4wd modes. Does the front work just like the rear open differential? If so, then what's the point of the CAD? I thought it was to allow the front wheel to turn at different rates when cornering, but if it's bypassed, won't that cause problems with sharp turns at low speeds? Anyway, here's how I spent my New Year's Day: Link to comment Share on other sites More sharing options...
Drahcir495 Posted January 2, 2009 Share Posted January 2, 2009 Anyway, here's how I spent my New Year's Day: :eek: :cheers: :clapping: I can't imagine working on the Comanche outside in the snow :bowdown: . Insane - Rich Link to comment Share on other sites More sharing options...
mvusse Posted January 2, 2009 Share Posted January 2, 2009 Yes, with the CAD always engaged the front axle does act as a solid axle, but it still has a differential. With the CAD disengaged you just spin the shaft with the least resistance, being the half shaft that ends at the disconnect With the CAD engaged, you still spin the shaft with the least resistance. Since there is no unconnected half shaft, that now becomes the wheel with the least amount of traction. To spin both wheels you need a spool or locker. I'm actually installing an Aussie Locker in my front axle some time this spring. Link to comment Share on other sites More sharing options...
jeepcoma Posted January 2, 2009 Author Share Posted January 2, 2009 Hey Pete, the shifter linkage you mention... would it happen to be the Novak SK2X? It looks like a nice piece but is pricey at $150 for some plates and rods :eek: Link to comment Share on other sites More sharing options...
Pete M Posted January 2, 2009 Share Posted January 2, 2009 Might be. I've never looked into it. I just remember someone saying it exists. :thumbsup: Link to comment Share on other sites More sharing options...
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