Thinking Cap Time - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > JK Jeep Wrangler Forum > JK General Discussion Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 01-27-2011, 11:07 AM   #1
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Thinking Cap Time

Okay folks, I've got a puzzler for you . . . .

For about three or four weeks now, my 2010 JKU manual trans with less than 10k miles has been making a high-pitched whining/ringing sound in some very specific circumstances.

The Jeep is at the dealership now, where I was able to replicate the ringing for one of the techs on a drive. He's stumped, but they're going to try and figure it out.

I thought I'd see if anyone here has any ideas. The parameters are as follows:

(1) Between about 1800 and 2200 RPMs in any gear except first, the Jeep gives off a high-pitch whine/ring.

(2) It's high pitch enough that persons with less than perfect hearing can't hear it. However, if you can hear it, it's maddening. The older tech I took on a drive couldn't hear it at all. When I took a younger tech, he heard it immediately.

(3) The Jeep must be in gear. The sound does not appear in neutral if you simply rev the engine through the RPMs.

(4) I can make the sound quit by either dropping off some of the RPMs or providing more RPMs. It only appears in very narrow spots, usually between 1800 and 2200 RPMs.

(5) The exact RPM it starts at/stops at varies somewhat, though it's usually in the 1800-2200 range. For example, today in sixth gear it appeared only at 1900 RPMs--any higher or lower and it was gone. In fifth gear it appeared at a slightly different RPM, but still between 1800 and 2200.

(6) Around town, the sound only appears during the brief time when you go through the particular RPM range, then disappears when you shift (and RPMs drop), only to reappear in the new gear when the RPMs get to the right range.

(7) On the highway or other long stretches of road, I can "hold" the sound in place by simply keeping the Jeep in the right RPM range. I can often keep it going for a mile or more. Because it appears at a common cruising RPM range (1800-2200), it can be very irritating whenever you "hit" the right spot on the tachometer.

Some observations:

(A) I can't be sure, but the absense of the sound in first gear may simply be because you tend to go through the revs so quickly in that gear. I haven't tried it in reverse.

(B) Both myself and the tech that heard it doubt it is a stuck brake, belt, or wind noise. The brake would make noise at any RPM, and problem belts tend to make a lot of racket when they first start spinning. Wind noise might appear/disappear at certain speeds, but this sound correllates to a specific RPM range regardless of overall speed.

(C) There doesn't appear to be any other symptoms. The engine runs fine, the transmission shifts fine, etc. Even when the ringing/whining is occuring, it doesn't appear to affect anything.

(D) It is definitely a change and the Jeep hasn't always done it. It's been going on about three or four weeks.

I'll let you know what the dealership says, but in the interim, who's got some ideas? Anybody?? I'm stumped.

Thanks.

MTH is offline   Quote Quick Reply
Old 01-27-2011, 11:17 AM   #2
Jeeper
 
JIMBOX's Avatar
 
Join Date: Nov 2009
Posts: 9,914
Sounds to me like "Throwout bearing harmonics"--

JIMBO

__________________
"ya gotta have class"
JIMBOX is offline   Quote Quick Reply
Old 01-27-2011, 11:28 AM   #3
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by JIMBOX View Post
Sounds to me like "Throwout bearing harmonics"-- JIMBO
Hmm . . . . Sounds suffiiciently amorphous and rare to be about right . . . .

The tech mentioned a potential bearing issue, but said it didn't "sound like a bearing." Of course, the sound of a bad bearing and the sound of bad bearing "harmonics" may be quite different. I like this possiblity . . . .

Anything you can think of that's bad about having issues with my "throwout bearing harmonics"? (Besides driving the driver insane.) How would one investigate whether a bearing was creating "harmonic" issues?
MTH is offline   Quote Quick Reply
Old 01-27-2011, 11:42 AM   #4
Jeeper
 
JIMBOX's Avatar
 
Join Date: Nov 2009
Posts: 9,914
Sometimes the Throwout brg won't show (sound), it's failing lube status without a transmission primary shaft load, but

There is an auto stethoscope, that the tech could use thru the bottom bell housing vent--now I don't know if they do that any more or if he would even need to nowadays, but

I've used my steth- quite a few times to locate knocks/whines/rattles, in outta the way places, but

It could be something entirely different, if it's only at one specific RPM it cold even be a heat shield near one of the exhausts, or the one above the muffler-

This'll throw ya, it could be one of the rear coil "isolators" in your suspension !!

Now I gotta hear what your dealer finds !!

Good luck

n JIMBO
__________________
"ya gotta have class"
JIMBOX is offline   Quote Quick Reply
Old 01-27-2011, 12:11 PM   #5
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by JIMBOX View Post
Now I gotta hear what your dealer finds !!
Me too. I called them and gave them your educated guesses as possible solutions and they seemed appreciative. The tech was pretty baffled this morning. It'll be interesting to see what they say.

Anyone else want to take a crack at this? So far we've got throwout bearing harmonics, heatshield near the exhaust or muffler, or a rear coil isolater in the suspension.

It's an open question folks, don't everybody try to answer at once!!
MTH is offline   Quote Quick Reply
Old 01-27-2011, 12:25 PM   #6
kik
Jeeper
 
kik's Avatar
 
Join Date: Dec 2008
Posts: 4,726
Images: 1
Drive shaft U-Joint.
kik is offline   Quote Quick Reply
Old 01-27-2011, 01:26 PM   #7
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by kik View Post
Drive shaft U-Joint.
Now that would really be interesting. I've got no lift yet, but it's still another good thought. Thanks.
MTH is offline   Quote Quick Reply
Old 01-27-2011, 01:34 PM   #8
Jeeper
 
JIMBOX's Avatar
 
Join Date: Nov 2009
Posts: 9,914
Good possibility !!

JIMBO
__________________
"ya gotta have class"
JIMBOX is offline   Quote Quick Reply
Old 01-27-2011, 01:34 PM   #9
kik
Jeeper
 
kik's Avatar
 
Join Date: Dec 2008
Posts: 4,726
Images: 1
Quote:
Originally Posted by MTH View Post
Now that would really be interesting. I've got no lift yet, but it's still another good thought. Thanks.
Yeah, this is something unusual. The reason I say u-joint, and I can be totally off base, is because that happened to a Corvette I had having a similar sound that you described. It will be interesting to see what the dealer comes up with. Hopefully it's something simple and easily repaired.
kik is offline   Quote Quick Reply
Old 01-27-2011, 01:44 PM   #10
ESP
Jeeper
 
ESP's Avatar
 
Join Date: Jun 2010
Location: NC
Posts: 11,501
The ringing in your ears is from the Justin Bieber concert you attended last night.

I'll be checking this thread to see what they find. Which dealer did you take it too?
__________________
98 XJ 02 TJ 10 JK 13 JK

2013 JK - Lifted w/ 35s - Bilstein 5100s - Monster TB - Chopped Flares - Can't Keep It Clean
ESP is offline   Quote Quick Reply
Old 01-27-2011, 02:00 PM   #11
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by ESP123 View Post
The ringing in your ears is from the Justin Bieber concert you attended last night.

I'll be checking this thread to see what they find. Which dealer did you take it too?
Ahh, of course! I also blast him at full volume in my headphones while driving. Ke$ha too, naturally. That could be it . . . .

Sport Durst (here), down the street from my house in Durham. If they can't figure it out, I might take it to the place you go in Cary. I'm concerned it's going to be one of those mysteries where they need "something else to go wrong" before they can figure it out.
MTH is offline   Quote Quick Reply
Old 01-27-2011, 02:18 PM   #12
ESP
Jeeper
 
ESP's Avatar
 
Join Date: Jun 2010
Location: NC
Posts: 11,501
Quote:
Originally Posted by MTH View Post
Ahh, of course! I also blast him at full volume in my headphones while driving. Ke$ha too, naturally. That could be it . . . .

Sport Durst (here), down the street from my house in Durham. If they can't figure it out, I might take it to the place you go in Cary. I'm concerned it's going to be one of those mysteries where they need "something else to go wrong" before they can figure it out.
I hear ya, I hope not but sometimes it goes that way unfortunately. Did it do this before the spacer and light mount install?
__________________
98 XJ 02 TJ 10 JK 13 JK

2013 JK - Lifted w/ 35s - Bilstein 5100s - Monster TB - Chopped Flares - Can't Keep It Clean
ESP is offline   Quote Quick Reply
Old 01-27-2011, 02:31 PM   #13
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by ESP123 View Post
Did it do this before the spacer and light mount install?
I'm pretty sure it did, yeah. Hard to recall exactly.

I have thought hard about whether any of my mods could be culprits--the front skid, the light bar, the air intake, the spacers, etc. But given the nature of those mods, I'd think any noise like the one I'm experiencing from those mods would really have to be related to wind. None of my mods move.

The ringing/whining sound really just doesn't "sound" like wind, and, perhaps more tellingly, it's correlated to engine speed (RPMs) rather than vehicle speed (MPH). Plus, the sound definitely didn't begin immediately after the install of any particular mod. It just jumped out at me one day while I was driving home from work.

It's something else . . . making me crazy too . . . .
MTH is offline   Quote Quick Reply
Old 01-27-2011, 02:46 PM   #14
Jeeper
 
JIMBOX's Avatar
 
Join Date: Nov 2009
Posts: 9,914
AIR INTAKE??-I didn't know you modded the Air Intake--

This opens up a whole new field of possibilities, including "gap velocity", dependant on airflow speed and wavelength-for high freq-

I can't wait to hear the answer you get !!

JIMBO
__________________
"ya gotta have class"
JIMBOX is offline   Quote Quick Reply
Old 01-27-2011, 02:55 PM   #15
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by JIMBOX View Post
AIR INTAKE??-I didn't know you modded the Air Intake--

This opens up a whole new field of possibilities, including "gap velocity", dependant on airflow speed and wavelength-for high freq-

I can't wait to hear the answer you get !!

JIMBO
Yep, you might remember this thread from a few weeks back where I "reviewed' the intake.

The sound didn't start for a while after that, though, so that doesn't look like a good culprit to me. BUT, if the dealer can't figure it out, I might toss on my old intake just to see . . . .
MTH is offline   Quote Quick Reply
Old 01-27-2011, 03:09 PM   #16
kik
Jeeper
 
kik's Avatar
 
Join Date: Dec 2008
Posts: 4,726
Images: 1
Quote:
Originally Posted by MTH View Post
Yep, you might remember this thread from a few weeks back where I "reviewed' the intake.

The sound didn't start for a while after that, though, so that doesn't look like a good culprit to me. BUT, if the dealer can't figure it out, I might toss on my old intake just to see . . . .
Oh, it could be temp. related with the air flow and as Jimbo indicated. I would go with the old intake now to rule it in or out before you go nuts at the dealer with them poking and prodding everything.
kik is offline   Quote Quick Reply
Old 01-27-2011, 03:14 PM   #17
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by kik View Post
I would go with the old intake now to rule it in or out before you go nuts at the dealer with them poking and prodding everything.
Definitely. If the dealer can't pinpoint it to something else, I'll swap them back and see if it continues. I'm all for ruling stuff out. Thx.
MTH is offline   Quote Quick Reply
Old 01-28-2011, 06:20 AM   #18
Jeeper
 
Join Date: Nov 2010
Posts: 212
I'm with JIMBOX and kik in thinking its probably something related to drivetrain harmonics. When I first read your post I was thinking the driveshaft was a little out of whack, like maybe it slung off the balancing weight or got dinged.
sheetsd66 is offline   Quote Quick Reply
Old 01-28-2011, 01:45 PM   #19
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
AND THE ANSWER IS . . . .

They don't know.

The drivetrain tech was certain he heard the ringing when I was driving. However, he could not replicate it on three drives over the past two days, nor could he replicate it with the Jeep on a lift with another tech driving it while the wheels spun in the air.

That's pretty amazing given that it happens every time it's driven. But I suppose I'm "well practiced" in finding the tone.

Without unbuilding the Jeep, they looked at everything they could think of that could be related to "drivetrain harmonics" and saw nothing amiss. No problems with the heatshield near the exhaust or muffler, nor a rear coil isolater. No worn or otherwise suspicious bearings. Interestingly, they didn't even mention the air intake.

The recommendation is to keep listening and bring it back if it gets worse or appears to affect anything.

Definitely frustrating . . . BUT I'VE MISSED MY JEEP, so I'm looking forward to getting it back!
MTH is offline   Quote Quick Reply
Old 01-28-2011, 02:12 PM   #20
kik
Jeeper
 
kik's Avatar
 
Join Date: Dec 2008
Posts: 4,726
Images: 1
The driveline won't act exactly the same without the effects of the weight load on it. However, I'm leaning towards the intake. I would swap the intakes at this point, at least then you'll know for sure. If you decide to do that let us know how you make out.
kik is offline   Quote Quick Reply
Old 01-28-2011, 02:55 PM   #21
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by kik View Post
I would swap the intakes at this point, at least then you'll know for sure. If you decide to do that let us know how you make out.
Unless something else suddenly goes wrong, I will definitely do a swap before the Jeep goes back to the dealer and post up the results. Thanks for all your help folks.
MTH is offline   Quote Quick Reply
Old 01-28-2011, 03:57 PM   #22
Jeeper
 
Join Date: Jan 2011
Location: Southern CA
Posts: 73
Images: 2
Thinking cap Time

Does your Jeep only do this when you are moving? The reason I ask is that I had an rpm specific whine in a 1999 Ford Explorer that sounded a lot like what you are describing, and come to find it was a serpentine belt idler pulley vibrating at certain rpms. I found that by mistake. It wasn't freezing up just a little bearing slop. $8.00 at Autozone, and the whining stopped.
TJ922 is offline   Quote Quick Reply
Old 01-28-2011, 04:24 PM   #23
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by TJ922 View Post
Does your Jeep only do this when you are moving?
Yes, only when I'm moving. If I just rev the engine in neutral, it won't do it--the transmission must be engaged. If you had a similar experience with serpentine I assume it occured even when the vehicle was in neutral, correct?
MTH is offline   Quote Quick Reply
Old 01-31-2011, 07:06 PM   #24
Newb
 
RNHdb25's Avatar
 
Join Date: Jan 2011
Location: Richmond, Va
Posts: 7
same problem

i recently bought a 99 TJ with 128k miles. 4.0L 5sp manual. i can't help but notice a loud whining sound when engine braking at any speed. the general consensus is a bad throw out bearing. might be helpful if you could get someone to record the sound when it is there and post a link to it.
RNHdb25 is offline   Quote Quick Reply
Old 01-31-2011, 11:51 PM   #25
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
Quote:
Originally Posted by RNHdb25
i recently bought a 99 TJ with 128k miles. 4.0L 5sp manual. i can't help but notice a loud whining sound when engine braking at any speed. the general consensus is a bad throw out bearing. might be helpful if you could get someone to record the sound when it is there and post a link to it.
Congrats on the TJ.

Interesting possibility. I never really engine brake, but in light of your post I tried it a number times going home tonight. No dice--mine only rings when I'm accelerating at certain RPMs. It won't happen while decelerating.

Also, I'm pretty sure it would be much too quiet for an iPhone or some such thing to record over the sound of the engine, soft top, tires, etc. It's very subtle. Passengers for example never notice it. Nor is it noticeable over the radio or even conversation.

Perhaps if nothing else this means my issue ISN'T a bad throw out bearing!
__________________
Mike
2010 JKU "Mountain" Edition
TeraFlex 2.5" Coil Lift : Old Man Emu Nitrocharger Shocks : 33x12.5R15 Goodyear DuraTracs : 15x8 Black Rock 909s : Other Stuff . . .
MTH is offline   Quote Quick Reply
Old 02-01-2011, 01:10 AM   #26
Newb
 
RNHdb25's Avatar
 
Join Date: Jan 2011
Location: Richmond, Va
Posts: 7
perhaps your pinion angles for the rear are out of alignment. that might cause whining under power
RNHdb25 is offline   Quote Quick Reply
Old 03-08-2011, 10:19 AM   #27
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
SOLVED.

It was the THROTTLE BODY.

This weekend I replaced my throttle body with the throttle body from a Dodge Viper. The whine instantly and completely vanished, and has not returned. Near as I can tell, as air was pulled over the stock throttle at certain RPMs, it whistled.

I'm going to do a "review" on the throttle body replacement when I have time along with pics and so on. If you're desperately curious, run a search on "viper throttle body" you'll see there's a few threads on it already. Regardless, in the interim, I wanted to mention that this issue has been solved totally by accident.

PS: For what it's worth, this means Jimbox and Kik were correct.
MTH is offline   Quote Quick Reply
Old 03-08-2011, 10:30 AM   #28
Jeeper

WF Supporting Member
 
Join Date: Feb 2011
Posts: 521
Images: 2
MTH - Was the throttle-body replaced with an after-market one or is it the stock one, and didn't you say that you had installed a TBS at one point? Was that part of the problem as well?
__________________
If you only have a Jeep, every problem appears as a rock. I like rocks.
trennmaschine is offline   Quote Quick Reply
Old 03-08-2011, 10:39 AM   #29
MTH
Jeeper
 
MTH's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 8,553
No, I have never installed a throttle body spacer. I understand they do nothing and, from looking at them, I can't imagine why they would.

To clarify, this weekend I replaced my stock throttle body, which had never been changed or modified in any way aside from being connected to an aftermarket air intake, with the stock throttle body for a Dodge Viper.

The whining sound, described in my opening post in this thread and which consistently appeared under the conditions I described right up until I installed the new throttle body, ceased and has not returned.

I AM A HAPPY CAMPER.

MTH is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Rampart Range, Colorado First Time :) aenima540 Trail Pics 1 06-13-2010 07:00 PM
89 Islander, love Jeeps but gotta sell, not enuf time and $$ cwweigle@hotmail.com WF New Member Check In 1 05-16-2010 07:55 PM
TJ Hardtop, rural FL half the time, Los Angeles the other half. Yep. WF New Member Check In 6 05-04-2010 06:14 AM
So you're thinking of joining the Navy... Jerry Bransford Off-Topic 13 05-01-2010 12:01 PM
10 Best Car Repair Tools of All Time larphead General Jeep Discussion 14 07-24-2009 05:29 PM



» Featured Product

All times are GMT -5. The time now is 04:19 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC