Stupid Über-Noob Questions

[TheAlmightySam]

Hey guys,
Threw a search out there for some of these, and most of my quandry came up with cures for death-wobble, which I luckily don't have. Hopefully I didn't miss an easy search term that would have solved my quandry, but "this thing makes a funny clunk-clunk-clunk when I slow down" doesn't come up with anything :) .

That said, I'm a new Jeep owner, having stumbled across a lovely blue '92 XJ, 4.0, AW4, NP231 on 30x9.5 BFG A/T KOs. Nice rig, and I like it a lot. Still, I have the following questions which should hopefully prove elementary to the minds here.

So, let's play.

1. The transfer case seems to jam up quite badly on occasion when trying to shift between the two ranges. Doesn't seem to matter whether I'm in park, neutral, reverse, or drive, and I know it's not bound up, because it's done it both on my perfectly flat, straight driveway and in gravel, where binding should be a non-issue anyway.

2. I'm assuming the t-case shifter is out of alignment, because although it goes into low just fine, it has a hard time keeping the front axle engaged. I have to pull the shifter back to keep it from being 2Low, and although 2Low is useful, that's not quite how I want this thing to work. Best thing is to just ditch the vacuum actuator, I know, but what's a good fix until I can do so?

3. When slowing down from speed, at about 25 MPH the vehicle will make a noticable "clunk clunk clunk," seemingly in time with the rotation of the wheels. U-joints have no play in them, the diff gears seem solid (very minimal play, nothing unexpected there). What be the culprit and the fix?

4. Okay, final question. I tore off a trans cooler line on a rock about a month ago. Patched it up with a bit of the coolant reservoir line, and it seems to be holding up just fine. However, ever since, the trans has very occasionally acted like it's "fallen out of gear." Even though I'm in drive, it'll just sit for a few moments and then come back to life, just like it was. Seems to be exaggerated by a hard stop, but that might just be my imagination. The gentleman at the local transmission shop mentioned something about the "internal seals being vulcanized," but I'm not sure whether or not to trust his advice. Thoughts?

Thanks a million in advance, guys!

[tommyr]

#1 there is a way to adjust the xfer case linkage. If i remember right its something like pull the lever all the way back to 4 lo. then loosen the lever linkage from the xfer case and put a 3/16ths shim behind the lever to keep it from being jammed all the way against the stop and tighten the linkage back up. Dont know if this is exactly what you are talking about or not. I don't have the vacuum actuator. Service manual has procedure for this -- I'm just going by memory.

#3. clunk clunk clunk......Let's see. Warped rotor banging against the pads trying to force the pads away from the rotor? Calipers not floating
properly? or axle u joints or axle CV joints.

4. Low fluid level?

[TheAlmightySam]

Hey, thanks for the reply!

I guess I should probably snag a service manual for this thing. Is one variety particularly better than another (excluding the FSM, of course, I haven't got the cash for that) for the Cherokee?

The one of the noise culprits you mentioned that seems on target would be the axle CVs, which narrows it down to the front axle. The U-joints seem fine, and the noise is unlike any caliper/rotor issue I've ever heard. That said, it seems a bit low-pitched to be a CV problem - it's not the usual click-click-click of a CV, and turning seems not to affect it. How ought I to go about inspecting the CVs on this beast?

Oh, and the transmission fluid level is fine, checked on the flat, idling in both park and neutral. I wish it was that simple...

Thanks for the help!

[Oizarod115]

only way ive ever heard of adjusting the linkage for 4x4 is to put the transfer case in nuetral, loosen the nuts and bolts, then put the lever in nuetral and tighten it back up.

[riverfever]

Do a search for threads dealing with transfer case linkages by the member named Matthew Currie. He has an excellent description of how to adjust it properly. It's quite easy and should solve your shifting dilemma. I would look at warped rotors for the clunking but it's tough to say over the net.

[TheAlmightySam]

Hey, thanks! I'll definately search those threads out!

As far as the clunking goes, (and I know it's really tough to diagnose sounds over the intarweb) do you think a warped rotor could cause a low-pitched "whump-whump-whump?" I'll have to get under there tomorrow night and look for uneven wear. Probably time to swap out the brakes anyway, this thing does NOT stop fast.

Thanks, guys!

[tommyr]

Dont forget to check e-bay for factory service manuals. Can sometimes get pretty good deals.
Can 92's have CV joints on the axles? or only U-joints? I dont know. If it has CV joints see if the boots are torn up. if so, probably good to replace the shafts, especially not knowing history of vehicle. If not, what you want to look for is (with either u-joints or CV joints) is with one wheel jacked up, ANY play between the outer (wheel) portion of the drive shaft and the inner (differental) portion of the axle shaft when you turn the wheel, you want to see the inner portion of the shaft turn exactly the same as the outer.
As far as the brakes, my wife's ZJ had a caliper guide pin that was not moving freely which would cause a clunk type noise. Usual clue to brakes is sound is in time with wheel rotation and applying brakes will make the sound change.
If changing brakes be sure to check the rubber brake lines to the calipers. New lines + bleeding of course, will get just about any sponginess out of pedal. Dont think XJ's are quite as bad as ZJ's or WJ's but these things do eat rotors....

[riverfever]

Do you feel the "whump" in the pedal? The rotors in these things suck bawls and always get warped. You will feel warped rotors in the pedal when you hit the brakes. If you feel it or hear it when you're on the brakes then I'd be leaning towards them being warped. You wont be able to see warping with the naked eye though. NAPA will probably turn them for 15 bones or so. Swap out the pads too. Good insurance and it will probably solve that issue.

[themangeraaad]

If your getting a service manual, go to autozone or whereever and pick up a Haynes manual. By far the best 15$ I have ever spent, and the best investment I keep in the back of my Jeep at all times.

[Menzenski]

2. I'm assuming the t-case shifter is out of alignment, because although it goes into low just fine, it has a hard time keeping the front axle engaged. I have to pull the shifter back to keep it from being 2Low, and although 2Low is useful, that's not quite how I want this thing to work. Best thing is to just ditch the vacuum actuator, I know, but what's a good fix until I can do so?
What do you mean by "ditch the vacuum actuator"? Your 92 shouldn't have one, unless I'm mistaken. Have you tried shifting the transfer case by moving the actual range lever? If not, crawl under your Jeep, follow the linkage to the lever on the t-case, and pull it all the way down (that's 4-low) and see if that makes a difference. Or maybe just crawl under and watch the linkage while someone else is in the Jeep shifting the t-case, and see if it needs to be adjusted (e.g., if the 4-low position on the shifter doesn't move the t-case all the way into 4-low).

3. When slowing down from speed, at about 25 MPH the vehicle will make a noticable "clunk clunk clunk," seemingly in time with the rotation of the wheels. U-joints have no play in them, the diff gears seem solid (very minimal play, nothing unexpected there). What be the culprit and the fix?
Check your rear driveshaft u-joints. Recently, my Jeep started to make a clunk like that when I let off the gas; it sounded like the transmission was full of rocks. When I pulled the rear driveshaft last week, I found out that both u-joints were toast. They were the greaseable kind, and it was clear that they hadn't been greased in a long time.

Your 92 should not have CV joints. Except for the 84-86 models, XJs didn't have CVs.

[TheAlmightySam]

I was under the impression that all NP231-equipped XJs had a vacuum-disconnected front axle... maybe this is wrong? I'm still learning...

The shifter seems to do the shifting just fine (aside from the awful binding mentioned above) - in other words, Low is really Low, etc. However, the Part Time light on the dash only lights up when I hold the lever back when in Low. Does the lamp being off mean the front axle is disengaged, or are the axle and lamp seperate systems? I should have been more specific, because now that I type that, it strikes me as possibly being a problem with the contacts that light up the Part Time lamp - sound feasable? And if the lamp is off, is my 4WD still engaged if the lever is in the right spot?

The U-joints didn't seem to have any play in them at all, which is good, I think. Glad to hear I don't have any CVs as well - after owning a 4WD Subaru, I'm so sick of CV joints...

I'm really leaning toward it being a rotor issue, because I can feel it in the pedal. I'll pull a wheel off and take a look. If I do need to replace the rotors, is there a specific brand you folks recommend? Also, are stainless braided lines available from any vendors, or are the stock rubber ones all there really is? The one thing I can't stand about the Jeep is how awful the brakes are on this thing, but I suppose I'm a bit jaded, going to work every day in a car with 14" rotors and 4-pots :D .

Thanks for all the help, guys! Much appreciated.

[Jess]

If your lever is not engaging your xfer case into 4-lo than it would be in neutral. If you can press the accelerator and go it has to be in gear. The connection on the light may be faulty.

[TheAlmightySam]

So, if the t-case is in 4WD (Low or High), is the front axle on a '92 de facto engaged? I was under the impression that I had a vacuum disconnect on the front axle in leu of locking hubs. Here's a pic:

http://www.ultimatesubaru.net/photos/data/892/frontpumpkin.jpg

Isn't that the vacuum disconnect line, or is that a diff breather?


The t-case engages 4High, neutral, and 4Low just fine, aside from the binding issues - my question is, is the Part Time light accurate in showing whether or not the front axle is engaged? If it's accurate, do I need to adjust the linkage to get the actuator to engage the axle properly? Or, if it's inaccurate, how do I fix it so it lights up appropriately when the t-case is in 4?

Thanks!

[Eagle]

I was under the impression that all NP231-equipped XJs had a vacuum-disconnected front axle... maybe this is wrong?
1990 was the last year with a vacuum disconnect front axle. And, as already noted, 1986 was the last year for CV joints. However, failing front axle u-joints can and do make a click-click sound when turning corners.

[TheAlmightySam]

So, if I don't have a vacuum disconnect axle, what's that rubber hose for? That's an honest question, no attitude. Is that a diff breather?

Does my front axle not disconnect at all, and the only connection is at the transfer case? That would make me awfully happy to know the issue is electrical rather than something mechanical or vacuum-related!

[karstic]

That rubber hose is the vent for the differential.

Correct. The T-Case actuates the 4wd.

Your clunk-clunk-clunk MAY (emphasize may) be cupped tire wear.

[TheAlmightySam]

Cool, solves problem #2! Is there a way to adjust the activation of the Part Time lamp on the dash, or should I just not worry too much about it?

I do have slightly cupped front tires, but I really can't imagine that they'd make that much noise at that speed, really. It seems to be when moving slowly, whether the brakes are depressed or not, and it goes away at higher speeds (35mph and up). There is vibration between 55 and 65, but I'm attributing that to either the cupped tires or a tire being out of balance, and I doubt the two problems are interrelated.

So, with #2 solved, and #3 probably being a warped rotor, that just leaves the major t-case binding issue and the "falling out of gear" issue with the transmission. Any guesses?

Thanks!

[tommyr]

Looks to me to be the Diff. breather. the vacuum motor for the disconnect sits on the axle tube.
As far as brakes go, the rotors warp. period. What I ended up doing is going to my local Murrays autoparts store and getting their Bosch rotors (I think they have moved to Raybestos now) WITH A 5 YEAR WARRANTY. Save your receipt & bring 'em in when you start getting pulsation in the pedal. I think they'll set you back about $60 each.

[Oizarod115]

this is what a vacuum disconnect D30 looks like...
http://img.photobucket.com/albums/v613/NickDOrazio/d35vsd60.jpg
circled in red is the v-disconnect housing.

[Littlewhitexj]

the whump whump could also be unit-bearings.

[Menzenski]

the whump whump could also be unit-bearings.
It could be. Jack up the front wheel, grab the top and bottom of the tire(6 and 12 o'clock) and try to rock the wheel back and forth. If there's any play, you probably need a new hub.

When my driverside hub went last fall, the vibrations would start right at 45 mph, and it felt like an out-of-round tire.

[5-90]

If your getting a service manual, go to autozone or whereever and pick up a Haynes manual. By far the best 15$ I have ever spent, and the best investment I keep in the back of my Jeep at all times.

Yech - I have a Haynes for the XJ - I use it to even up that odd leg on one of my workbenches. Chilton's is FAR superior to Haynes!

Granted, I've used Haynes on imports every now and again, and it does cover some things for imports that Chilton's doesn't (although I have no idea what - it's been years...) but a Chilton's will cost you the same as a Haynes (ish,) and give you a better book for your bucks.

As far as the FSM goes, I've been collecting them - so if you have any questions that your SM won't cover, ask here, and someone with your year will probably chime in. Do please be at least fairly specific tho - asking for a "full procedure" will probably not get you any answers. Asking for "here's what I've got - what am I missing?" is far more likely to work. We're all willing to help, but help us help you. Most of us will see no reason to do as much work as you are - without the vehicle handy!

As far as "noise diagnosis on the Internet," here are a few pointers...
1) Note as much as possible in re: the noise. Conditions, roadway, driver action - Hell, even weather changes can be helpful! If you give "too much" information, we'll just discount what we don't need. If you give "not enough" information, be prepared to answer questions. A lot of them!
2) If possible, record a digital clip of the sound. Don't post it, but it's possible we'll ask for you to email it somewhere, and having the clip already digitised is a huge help. If you don't need it, just delete it once the problem's fixed - or .zip it up along with a text file detailing what the problem actually WAS, and how you fixed it - since I'm thinking about starting a "troubleshoot by sound" archive somewhere anyhow, and someone else might have a simliar idea. I'm just not about to "break" something just to record a noise...
3) Be descriptive, and have notes for when someone asks you to be more descriptive. Rhythm, circumstances, speeding up or slowing down - all are cues to where the noise may be coming from. And, to what may be causing it.

It's possible to "diagnose by sound" remotely, but it's going to take a LOT more effort on your part to make the idea work!

As far as the test that Mambeu gave you - you'll want to watch the backside and the steering knuckle while you do it. That test will also point up faulty/failing/failed ball joints, and you'll have to see what's moving to narrow it down. It's easier, I think, to take the tyre off and use a screwdriver to pry on the unit-bearing flange (where the studs are,) and that will allow you to fullly isolate its motion. I go so far as to use a dial indicator, but that's just me. Whenever you try to isolate a failure by moving the parts, you'll want to make sure that ONLY the part you're checking moves, or you can get a good look at what all MIGHT be moving, so you can isolate what IS moving. If you shake the tyre, and decide it's your hubs, you're going to feel silly after dropping $200 on hub bearings, and finding out that you'll have to do ball joints.

Also, "loose hubs" in the wiggle test may be caused by the mounting screws working loose - LocTite is a good idea here, and torque to 75 pound-feet. You'll need either a 12m/m 12-point socket, or a 13m/m 12-point socket, I don't recall which.

5-90

[black93xj]

A leaking rear wheel cylinder will help cause the noise you described and I would just replace the front rotors in your case. I had the same noise reaplaced all of the U joints in both drive shafts and the front axle. After all that work and money the noise was still there. The noise ended up being a combination of the leaking wheel clyinder and the warped rotors if your brake pedal has a pulse the rotors are the cause. My wheel cylinder was not leaking much just enough to go through so fluid over a long peiod of time.
Also on my 93 when shifting from netural to low the jeep sometimes needs to roll just a little for it to go in. Hi range does not bind because that is a shift on the fly, where low you have to go through netural in the t-case.