Wasn't the SYE, what the he!! could it be!?!?!

[Safari Ary]

For those of you that had been following my "rear axle woes" thread, I originally thought it was my RE hack 'n tap SYE, since there was a noticeable amount of play in the splines between the flange and the output shaft. Well, I replaced the output shaft along with the RE flange, and to my GREAT dismay, the helicopter sound hasn't gone away in the least. What the heck could this be?? Could a U-joint in my rear DS be bad even though I don't see ANY play in it whatsoever?

My patience is wearing thin and my parents' is even thinner(NOT a good thing). Please help!!

Ary

[RCP Phx]

Since are vehicles are very simular I would guess your still having issues with the 8.25" and your driveline!The hack/n/tap kit didnt work for me so I went to the JB kit.I still have a "droning" noise above 60mph which I attribute to the 8.25. I need to change gears again and add a ARB so Im seriously thinking about a D44 instead of investing more money on the 8.25!

[Safari Ary]

I was talking to Andy at the Carolina Rock Shop and he said it sounded like a carrier bearing. He said I should pull the cover and if the fluid was greenish and foamy, that it was prolly the bearing. The noise seems to have died down with a little bit of driving, I get a clunking off the line, but if I play with it a little once I'm up to speed I can reduce the noise to a simple droning as opposed to the helicopter(thud thud thud thud type whir). I was supposed to drive to washington today, cape hateras on Tuesday, then up to Tech on Friday(the shortest travel time is 4 hours, the longest, 8) so I need to have my Jeep running NOW. I've got the master rebuild kit for the 8.25 as I have an ARB and 4.56s sitting here to be installed, but I'm thinking I can just use the carrier bearings from the kit and change them if that's the problem. Anyone else? Thanks

Ary

[Safari Ary]

Update: Looked at the fluid in the rear-end. It appears grey and non-foamy. Maybe SLIGHTLY milky, but not really. The more I think about it the more I think that I had driveline vibes that wore out my SYE and I fixed the symptom but the problem is still there. I wish someone in this town stocked shims, sure would make it easier. I'm gonna try to snap a pic to see if you guys think the angle at the pinion could be the problem. I really don't think it's that bad, I admit it's not ideal, but I didn't think it would cause all of this. I'll post again with a pic

[Safari Ary]

http://filebox.vt.edu/users/arebrahi/Jeep%20pictures/Driveline%20angles/103-0357_AUT.JPG

http://filebox.vt.edu/users/arebrahi/Jeep%20pictures/Driveline%20angles/103-0358_AUT.JPG

It's hard to show the angle exactly 'cause I can't get my camera in there very well, but the second pic shows the angle best. It's not really bad at all I don't think, but maybe I just don't know enough to tell the diff. Thanks guys, I'm really countin on you.:o

Ary

[EricsXJ]

Ary,

At the risk of sounding like a total idiot I'm going to throw this out and see what you think. (I might be way off I know) but...

Are you sure this "helicopter sound" is a sound coming from the driveline? Sometimes when I drive with certain windows open on the freeway I have a perfect "helicopter sound" inside the cab from the wind blowing in.

Also, your pinion angle looks good to me...

[Safari Ary]

Originally posted by EricsXJ
Ary,

At the risk of sounding like a total idiot I'm going to throw this out and see what you think. (I might be way off I know) but...

Are you sure this "helicopter sound" is a sound coming from the driveline? Sometimes when I drive with certain windows open on the freeway I have a perfect "helicopter sound" inside the cab from the wind blowing in.

Also, your pinion angle looks good to me...

Y'know, I hadn't thought of that, and it would be me that would be going through all of this when it was simply the window being down. But alas, I'm not so lucky. It does it with the windows up, down, and everywhere in between. It also does this at all speeds. I have tried to check the DS for play but everytime I grab ahold of it and try to wiggle it, there is no play. I've wiggled it so hard that the entire transfercase and transmission move. I'm at a loss. Thanks for your help guys

Ary

[STRYKER]

Ary.... take it for what it's worth...
But it appears to me that from the angle, you could probably go up with the pinion ... roughly 2* (although I'm working from a picture)

As long as your angler finder tells you that you have not exceeded a difference of 1* between the shaft tube and the actual pinion output. You want to keep the pinion 1* less than the number you arrive at as the difference in the two...

That'll keep it from making noise at full acceleration.

[Safari Ary]

Deano, I appreciate it, however what really gets me is that this just started and my angle was always like that(started kinda all of a sudden, not gradually). I pulled the rear DS and the ball and cup section of the CV joint seems to be sloppy, I'm in the midst of disassembling the joint right now to see what is needed. There is no grease fitting for the ball and cup, although it seems there should be. I think I found the problem(crossing fingers). Next thing is to order 2* shims. Thanks

Ary

[STRYKER]

Originally posted by Ary'01XJ
Deano, I appreciate it, however what really gets me is that this just started and my angle was always like that(started kinda all of a sudden, not gradually). I pulled the rear DS and the ball and cup section of the CV joint seems to be sloppy, I'm in the midst of disassembling the joint right now to see what is needed. There is no grease fitting for the ball and cup, although it seems there should be. I think I found the problem(crossing fingers). Next thing is to order 2* shims. Thanks

Ary


If it's loose, in a short amount of time, it's compensating for another problem. Just went thru this! :)

[Safari Ary]

Well, I redid all the U-joints in the DS, even though they all seemed fine. The ball and cup seemed fine, but I packed them as full as I could with grease. And of course, not a damn thing changed. I took it to my friend who's a trained dodge mechanic, and he said it's gotta be the CV joint still or in the rear-end. I'm going out of town tomorrow, I'll tear open the rear-end on Monday night. Thanks guys, keep the ideas comin!

Ary

[Carpenter]

Ary, try pulling the rear driveshaft and taking a spin in 4wd. This will rule out the possibilty of the rear shaft or pinion angle being your problem. If the noises are gine, it's the driveshaft or pinion angle. If the noise is still there it's the rear end. If you have gears and a locker to go in anyway and the problem turns out to be a bearing you really should go ahead and do all the work at once. The 8.25 rear ends are a bit tricky to work on anyway, might as well get it all done once rather than twice. Also, don't overlook the wheel bearings if you're having the rear end rebuilt.

[Safari Ary]

Wes, here's the problem, since the problem only occurs during load, it could still be the rear-end. When I was driving around in 4wd last week the sound was gone. But I'm not entirely convinced that it is the DS. The fluid in the rear-end is a light grey, which my mechanic friend said means there's metal in there. I'm gonna crack the diff on Monday since I'm leaving town right now and see what comes out. I agree about the locker and gears, but I'm stressin on the $$ aspect of it. We'll see how much the 'rents are willing to lend me. Thanks

Ary

[rixXJphx]

Ary-
I think carpenter meant remove the rear DS and put it in 4wd hi, effectively driving FWD.

If noise is gone, then problem is the removed DS.

If noise remains, the problem is prolly in the rear axle (which would still be turning in its bearings, albeit with no load on the ring-&-pinon).

[Matt99XJ]

Ary I am having the same exact problem. A humming/droaning sound at 60+ and it gets worse the faster I go. Does yours get worse the faster you go? Mine does it when I am on the gas and when I am coasting, it just changes the tone.

All of my angles are good, U-joints are good, driveshafts are balanced.

If I take my front shaft off the noise is WAY less noticable. I thought that it was something in the front for the longest time, now I am sure it is coming from the rear. I pulled my rear cover and the fluid looked great.

I have had a couple people tell me it could be either a pinion or carrier bearing in the rear axle. I don't see anything wrong with them though.

Let me know if you figure anything out.

[Safari Ary]

Originally posted by rixXJphx
Ary-
I think carpenter meant remove the rear DS and put it in 4wd hi, effectively driving FWD.

If noise is gone, then problem is the removed DS.

If noise remains, the problem is prolly in the rear axle (which would still be turning in its bearings, albeit with no load on the ring-&-pinon).

I know this, but the problem is that the noise only occurs under load, thereby, if I remove the DS the rear diff is not experiencing load and thereby cannot be elimintated as a factor. So it could still be either one.

Matt, the sounds starts right from the second I start moving as a thud thud thud that sounds like a worn u-joint, except it's not, 'cause they're all new. Thanks

Ary

[TOZOVR]

Originally posted by Ary'01XJ
I know this, but the problem is that the noise only occurs under load, thereby, if I remove the DS the rear diff is not experiencing load and thereby cannot be elimintated as a factor.
Ary

But you can elimninate everything else Tcase related, as of right now you're still speculating...if there's no noise you know it's either the DS or the Rear....if there is noise you know it's neither of them....

Good luck Bruddah.

[Safari Ary]

Where's your cape captain obvious?? :D I know it's not the T-case, I know it's either the DS or rear-end, I'm just speculating as to which one it is. The diff cover comes off bright and early tomorrow to see what's goin on in there. Wish me luck

Ary

[Carpenter]

Like I said before, pull the rear shaft and drive it around in FWD, that will allow you to rule out the driveshaft. If noises are still there, rear end, if not, driveshaft.

[96xjeeper]

I have to agree with Carpenter, pull the rear DS out, put it in 4 hi and drive around a few milew, get up to speed, load shouldn't matter. If the noise still occurs with the DS out you know it is the Axel, or were all just way off and its something totally different. If the noise id gone wit the DS out it has to be the DS itself or one of it's components.

[Rev Den]

When you say you re-did the U-joints, did you replace them? It almost sounds like you took them apart and re-lubed them, but did not replace them. Any chance you can get it up on stands, apply some brake, and give it some gas? Maybe a brave soul can use a "listening aid" to try to id where the sound is coming from.

Before you all jump on me for suggesting this......

Make sure you use jack stands on a firm level surface

Have room in front of you in case it drops

Have your helper in the truck, you do the listening with a LONG pipe, and a rubber hose to your ear, so if it does fall you are out of the way.

I do not recommend this, but it is an idea.....just be as safe as possable.


Rev

[4ward]

Den, we do that all the time with the race car. Nothing like seeing a tire spinning at 140 mph 5" from your face :eek:

Ary, I'm still thinking it's a u-joint phase issue. If it's only coming under load, I'm guessing your springs are wrapping up a bit and throwing them out of phase enough to make your sounds.

Oh yeah, if you're going through the pains of greasing the cups in a joint, just replace the darn thing. I thought my joints were good in my rear shaft, did the grab and shake- everything was solid. Now that I have it out of my heep, I can see that it needs replaced in a bad way. Actually, it shoulda broke instead of the 60 shaft on the pad.

[Safari Ary]

Well, to clear it up, I replaced all the U-joints. The Heep is at the dealer right now(my parents didn't leave me much choice, they were tired of me having my Jeep in pieces in their driveway which is definately understandeable). The guy just called and insists that I need to put in a T-case drop and that "no, shims won't fix your angle problem." I asked then "what exactly do shims fix then?" He was silent. I asked him to at least look at the fluid in the rear-end and see if anything looks out of the ordinary.

I really didn't think the angle was that far off, and the old u-joints were in pretty good shape(no play or anything, although the grease did look a little burnt? maybe not in so good a shape afterall?). Maybe it is the angle though.

I had the Jeep on stands and was letting it idle(damn thing goes 40 at idle with no load) and that's when I saw the problem with the SYE flange. Do you guys think the bind in the u-joint at the pinion could have caused vibrations that would have loosened the splines on the flange and caused what I originally thought was the problem? Also, wouldn't I have felt the vibes that were bad enough to cause that kind of damage? Just trying to figure this out. Thanks guys

Ary

P.S. Is there any reason aside from clearance to not put on a T-case drop with an SYE?

[bradlyw]

no reason u cant put a t-case drop in with an SYE...but the mechanic doesnt know what he's talkin about...one of the main points of an sye is to make it to where u dont need a t-case drop...so really there is no point in putting one on...that wont fix ur problem man.

Brad

[Safari Ary]

Originally posted by bradlyw
no reason u cant put a t-case drop in with an SYE...but the mechanic doesnt know what he's talkin about...one of the main points of an sye is to make it to where u dont need a t-case drop...so really there is no point in putting one on...that wont fix ur problem man.

Brad

Well, he's partially right, *I think*. He knows the formula to solve a problem, but he doesn't know the theory behind the formula. Chrysler says "if you have vibes, put in a T-case drop" So that's what he tells me. A t-case drop I believe would solve my problem, but I'd like to avoid it. I think I'm also in denial because I can't believe this problem would be as simple to fix as adding some 2* shims after I spent all that time replacing the output shaft and rebuilding the rear driveshaft. Oh well

Ary

[ChiXJeff]

Ary, that SYE flange should spin rock steady and concentric. Have you tried pulling the rear D/S and running it in 2wd to see if the shaft spins straight, or does it wobble?

Personally (and this is only a gut feeling) I'd bet on a runout problem on the shaft. Yes, I know, new shaft and flange. How about bearings?

[Safari Ary]

Last time I checked the shaft was spinning straight. It doesn't make any noises whatsoever when coasting which is what bugs me, if it were bad angles, they would be the worst during coast(maybe no load means less binding??). Also, if it were a loose bearing on the output shaft, wouldn't it wobble while coasting too?? I'm at a loss, and the dealer is being useless. Thanks guys

Ary

[Flowers]

First off, and I'm trying to be a dick, it's just reality, if you can't deal with a few vibes and the idiosyncrasies off a modified Jeep, then maybe you should consider a Passat.


[QUOTE]Originally posted by Ary'01XJ
[B]Last time I checked the shaft was spinning straight. It doesn't make any noises whatsoever when coasting which is what bugs me, if it were bad angles, they would be the worst during coast(maybe no load means less binding??).

No, your pinion could be too high. Have you measured your angles yet?

Also, if it were a loose bearing on the output shaft, wouldn't it wobble while coasting too??

Not neccesarily. But if it did, you may not feel it without it being under load.

I'm at a loss, and the dealer is being useless.

Most are!

If you have a vibe that is only noticable under Accelerration OR (emphasis on OR) Deceleration it's angles. If it's noticable on acceleration AND (emphasis on AND) deceleration it's a loose sumpin' or other.

Flowers

[urbanXJ]

IMHO, dont pay the dealer to replace the anything.

It's an 01 correct?
Are you under the 36K mile mark?
If so, what does dealer say about the mods and warantee coverage?

I had copter sound anytime I was not accelearating.
2* shim made no diffrence.
AA kit and woods shaft made it all better.

[Kejtar]

Flowers.... I think you're missing a point.... It's not an issue of a bit of extra noise, but the issue that comes down to the fact everything was good after installs, he was running it for a while.... and suddendly extra noise started which is never good..... there was no mods done between no noise and start of noise (as I understand) so that means that something wore out or is wearing out....

Kejtar

[Safari Ary]

Flowers, I respect your input, but if you ever rode in my Jeep, you'd understand that this is not simply an idiosyncracy. People ride in my Jeep all the time and they're like "what's that squeak, what's that clunk, etc etc" I can deal with those things, but this thing literally sounds BAD, and it came out of no where.

Yes the Jeep is an '01, no it's not under warranty(56k miles, I drive a lot). Went to DC, then to Winchester, then back home in a day and a half, that's 700 miles, on a whim.

Anyway, the dealer called, they say there's definately something going on in the rear diff judging by the fluid. They want 200$ just to crack the diff and inspect, I told them to piss off and I'd be there to pick it up shortly. I'm gonna take it to Tim Shaker of www.shakerbuilt.com and have him install my gears and ARB and hopefully take care of the problem in the process since the entire diff's guts will be new at that point. Thanks for the help guys, I'm off to the outer banks for a couple days, I'll report back when I know something. Later

Ary

[Carpenter]

The way you describe the noise and how it comes and goes it sounds like an angularity issue. However, since you say it happened all of a sudden that doesn't make sense. You still really need to pull the rear shaft to help further diagnose the problem. Heck, it wouldn't hurt to do the same with the front just to know you're not chasing your tail. You also should measure the rear pinion and driveshaft angles. All the information you can provide will really help us and maybe we can help you.

[Carpenter]

Originally posted by Ary'01XJ


I'm gonna take it to Tim Shaker of www.shakerbuilt.com and have him install my gears and ARB and hopefully take care of the problem in the process since the entire diff's guts will be new at that point. Thanks for the help guys, I'm off to the outer banks for a couple days, I'll report back when I know something. Later

Ary

Make sure he replaces the wheel bearing too. They don't cost much and it only makes sense to do it while the rear end it torn down. Also, have him check your rear driveshaft angle for you for giggles.

[STRYKER]

Originally posted by Carpenter
Make sure he replaces the wheel bearing too. They don't cost much and it only makes sense to do it while the rear end it torn down. Also, have him check your rear driveshaft angle for you for giggles.

Doesn't look this bad in the pics...
But do me a favor....

Measure the angle of the driveshaft itself with an angle finder. Tell me if you're close or exceeding 15*.
Just a hunch...

[goldxj]

I believe you were on the right track when you suspected the CV. I'm running a very different set-up then you, but, you're describing the exact scenario I dealt with for a few weeks. I'm lucky to have a DS shop in town (I should say a damn good DS shop). I pulled the rear shaft out, basically out of desparation, and low and behold, the CV was shot. When I checked the shaft, when it was on the truck, everything was tight, the rearend had just been rebuilt wheel cylinder to wheel cylinder(gears/bearings/carrier/seals/brakes/etc.) so I had a pretty good size list of suspect parts. After going over everything twice, it came back to the DS. I put the shaft in(after the CV was replaced, not rebuilt) about 3 weeks ago, and so far no noise. Good Luck.

goldxj

[XJCherokee99]

sorry to hear about the vibes, but i hear ya on the shim deal. I finally ended up ordering some from RE because not one auto parts store carried ANY around my town. pretty rediculous if you ask me.......:rolleyes:

[Safari Ary]

Ok, back from Tuna fishing. What a great time. :D

Just to clear things up, I have run the truck with both front and DS's removed individually. The noise would occur with both in, and with the rear one in. However it would go away with the front one in and the rear one out. Looking at the pinion to DS angle I really don't think that's the problem because I've been behind my Jeep when it was floored and I definately have an axle wrap problem. Therefore, assuming it's the angle, it would theoretically go away during varied acceleration. However, it does it under the faintest acceleration, i.e. just letting the Jeep idle off the line, and it does it all the way up to full acceleration. Now a blown CV could be another problem altogether, but since there was a good bit of metal in the rear diff, I'm betting that's my problem. If not, well, I got my ARB and gears installed which I'd been trying to get to do for a year now(literally). So it's not a loss. I'll keep ya guys posted, thanks

Ary

[cbremer]

hopefully your gears solve it! i had a rapid ticking sound upon deceleration that varied with vehicle speed (not necessarily braking, just taking my foot off the gas) a while back and it turns out that i had a chipped pinion tooth. of course, at the time, my new gears were only in for 2 weeks and had to be replaced :(

[Flowers]

BTT

Ary,

Any updates on the vibration?

Flowers