drivetrain noise when i let off the gas - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > TJ Wrangler Technical Forum > drivetrain noise when i let off the gas

SPARTAN LOCKERS are on sale BIG TIME at ROCKRIDGE 4WD!ROCKRIDGE4WD Introduces a NEW Jeep Wrangler JK *led* tail ANOTHER Rockridge4wd Creation!! Spare Tire Carrier Delete

Reply
Unread 03-09-2010, 11:09 AM   #1
leolufse
Registered User
2006 TJ Wrangler 
 
Join Date: Apr 2003
Location: Atlanta
Posts: 242
drivetrain noise when i let off the gas

When I'm on the highway and let of the gas and coast I begin to hear what sounds like roaring tire noise. If I put the gas back on, it goes away.
Its not super loud nor does it sound/feel like anything is "loose".
The jeep is a sport with the normal d30 and d44 axle combo, 3.73 gears, and 6 speed manual. Very low miles (22,000).
Its got brand new tires and all fluids changed and none of that made a difference.
Perhaps it is normal, but my 01 didn't seem to do this.
Is there something I should check?



leolufse is offline   Reply With Quote
Unread 03-09-2010, 11:36 AM   #2
Hotrod97z
Registered User
2003 TJ Wrangler 
 
Join Date: Jan 2004
Location: .....
Posts: 185
An incorrect ring/pinion setup is possible, but not likely and shouldn't be an issue if it only has 22k miles. It could be a bearing or a U-joint. Have you checked the diff fluid to make sure its full? Is it coming from the front/back/both? Have the gears been changed? How loud is it? All terrain and Mud terrain tires have inherent noises.
__________________
Alan

'03 TJ
Hotrod97z is offline   Reply With Quote
Unread 03-09-2010, 12:43 PM   #3
Ulumanati
Registered User
2004 TJ Wrangler 
 
Join Date: May 2007
Location: Texas
Posts: 356
I've got the exact same problem and was told it had to do with the rear pinion bearings.. Either going bad or lost their preload. And mine only has 20k miles too which is why I was surprised
__________________
2004 Silver Jeep Rubicon
6" Nth Degree Longarm Kit
Ulumanati is offline   Reply With Quote
Unread 03-09-2010, 12:49 PM   #4
VanBCguy
Web Wheeler
 
VanBCguy's Avatar
1999 WJ 
 
Join Date: Jun 2009
Location: Vancouver
Posts: 1,954
Can you describe "roaring tire noise" in more detail?
VanBCguy is offline   Reply With Quote
Unread 03-09-2010, 02:05 PM   #5
ps49556n
Registered User
2006 TJ Wrangler 
 
Join Date: Oct 2009
Location: NYC
Posts: 145
We need more detail of this noise...I know when I am driving there is always noise when you are in between putting torque to the drivetrain and no power at all...this is the trans making noise.
ps49556n is offline   Reply With Quote
Unread 03-09-2010, 04:00 PM   #6
leolufse
Registered User
2006 TJ Wrangler 
 
Join Date: Apr 2003
Location: Atlanta
Posts: 242
Its subtle, but if anything I hear it more on the right (passenger) side and rear.

The jeep has stock suspension and gears. The noise is there when I let of the gas in gear. Pushing in the clutch doesn't affect the noise. If I power back on the gas, it stops. If I let of the gas its there again.

When I say roaring tire noise, think of mud terrain lugs rolling on asphalt. Its not my tires because the sound stops when I stop coasting. It is a very on/off.

I had a bad wheel bearing on a car once and it was very different than this.
It would get louder with speed and coasting or power didn't make it stop.

I would guess ring and pinion noise from the rear, but the fluid is fresh and full. I changed it with RP, but it was doing the exact same thing on the stock fluid. The RP didn't make it worse or better.

Tell me about "rear pinion bearing pre-load". Is this somethig I can check/adjust?
leolufse is offline   Reply With Quote
Unread 03-09-2010, 04:12 PM   #7
Ulumanati
Registered User
2004 TJ Wrangler 
 
Join Date: May 2007
Location: Texas
Posts: 356
Yes what your describing is exactly what I have. Its like a rumble as soon as you let off the gas, they thought it was my tires but I verified that it isnt that or my driveshaft for that matter. The only thing is that mine happens anywhere from 30-40mph, if i let off the gas at a lower speed it doesnt happen for some reason. WHat speeds does yours happen at?

The preload has to be checked by a gear specialist who knows what they're doing, they gotta inspect the bearings to make sure they aren't going bad, and to do that they gotta open up the rear diff.
__________________
2004 Silver Jeep Rubicon
6" Nth Degree Longarm Kit
Ulumanati is offline   Reply With Quote
Unread 03-09-2010, 05:30 PM   #8
NorCalCon
Registered User
2006 LJ Wrangler 
 
Join Date: Oct 2008
Location: Sacramento
Posts: 673
Does the Jeep have a cold air intake, or anything other than the stock setup?
NorCalCon is offline   Reply With Quote
Unread 03-10-2010, 09:56 AM   #9
leolufse
Registered User
2006 TJ Wrangler 
 
Join Date: Apr 2003
Location: Atlanta
Posts: 242
Quote:
Originally Posted by NorCalCon View Post
Does the Jeep have a cold air intake, or anything other than the stock setup?
I have a banks cat back exhaust that pops and grumbles when I let off the gas, but this noise is not related to that.

Stock air intake and stock everything else.
I guess I'll just have to live with this mild noise until it gets to the point I can pinpoint exactly where it is and then figure out what it is.

leolufse is offline   Reply With Quote
Unread 03-10-2010, 10:37 AM   #10
NorCalCon
Registered User
2006 LJ Wrangler 
 
Join Date: Oct 2008
Location: Sacramento
Posts: 673
My cold air intake makes a sucking air roaring noise when I let off the gas at speed. I just replaced a unit bearing that gave a roaring/grinding sound only when I was coasting. I first heard it when I was getting off the freeway.
NorCalCon is offline   Reply With Quote
Unread 03-10-2010, 11:22 AM   #11
Hotrod97z
Registered User
2003 TJ Wrangler 
 
Join Date: Jan 2004
Location: .....
Posts: 185
Just drive it and see if it gets worse.
__________________
Alan

'03 TJ
Hotrod97z is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.